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Concourse 2

Adjectives

adjectives

Adjectives are a major word class and this guide is accordingly quite long.
If you are here for the first time, the advice is to work through it sequentially but if you are returning to check something, here's a list of the contents to take you to its various sections.
Clicking on -top- at the end of each section will bring you back to this menu.

Definition Adjective formation Stative vs. Dynamic uses Predicative vs. Attributive Inherent vs. Non-inherent Complementation
Double adjectives Markedness Proleptic uses Adjectives from / as nouns Post-positioned attributive adjectives too, enough and so
Epithets vs. Classifiers Gradability Participle adjectives Adjective ordering Co-ordinating adjectives Comparative and Superlative


define

Definitions

Easy questions:
What's an adjective?
Can you tell a word is an adjective by looking at it and seeing how it behaves?
Can you give a brief definition of 'adjective'?
Click here when you have answers.

adjective 1

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form

Forming adjectives

Many adjectives are not formed from other word classes and are, indeed, often the bases from which other word classes can be formed so, for example, the adjective able can be used as the base to form ability, the adjective clean forms the base of the noun cleanliness and, by conversion, the verb clean and the adjective difficult forms the base of the noun difficulty.  There are hundreds more examples and, of course, the adjective is often the base from which adverbs are formed.

However, there are conventional ways to form adjectives from words in other classes:

From nouns:
Adding -ly as in
    friend → friendly | mother → motherly | home → homely etc.
Adding -y as in
    grass → grassy | leaf → leafy | hair → hairy etc.
Adding -al as in
    music → musical | function → functional | occupation → occupational etc.
Adding -ic as in
    hero → heroic | metal → metallic | patriot → patriotic etc.
Adding -ese (for nationalities) as in
    Japan → Japanese | Siam → Siamese | China → Chinese | Vietnam → Vietnamese etc.
Adding -ish as in
    fool → foolish | child → childish | man → mannish etc.
Adding -ous as in
    courage → courageous | advantage → advantageous | synonym → synonymous etc.
Adding -less as in
    clue → clueless | accent → accentless | spot → spotless etc.
Adding -ful as in
    man → manful | art → artful | beauty → beautiful etc.
Adding -like as in
    child → childlike | life → lifelike | dream → dreamlike etc.
From verbs:
Adding -ful
    help → helpful | hope → hopeful | boast → boastful etc.
Adding -ive as in
    attract → attractive | select → selective | abuse → abusive etc.
Adding -able as in
    drink → drinkable | fix → fixable | do → doable etc.
Adding -ing or -ed or using the irregular participle form as in
    surprise → surprised / surprising | break → broken / breaking | sink → sunken / sinking etc.

Simply alerting your learners to the adjectives which may be formed from words they encounter is a useful way to increase their personal lexicons quite painlessly.
It is also the case that many of the suffixes above can only be adjectival in nature and that helps considerably to unpack the meaning of what learners see and hear.
Unfortunately, it is also the case that many adjectives do not have a distinctive form in English (unlike some other languages) so words like broad, hollow, tight, faint, brief, blue, rotten, deep, old, young and hundreds more can only be identified as adjectives by seeing what they do in a sentence, i.e., identifying their grammatical function.  Even that, as we shall see, is not always as straightforward as spotting the relationship between the word and a noun.

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Adjectives and Syntax


dynamic

Stative and Dynamic uses

Most adjectives are stative.  I.e., they refer to a state in being or a condition, for example:

  • The milk smells sour
  • The tall girl
  • The blue window frame
    etc.

The milk cannot become fresh, the girl cannot affect how tall she is and the window frame will remain blue.
There are two consequences:

  1. Stative adjectives are not used with progressive tense forms: we cannot have
        *the milk is smelling sour
    or
        *the girl is looking tall.
  2. Stative adjectives are not used with imperatives: we cannot have
        *Be tall
        *Don't be French
        *Be young
        *Be important
    for example.

Dynamic adjectives, by contrast, are to some extent under the control of whomever or whatever they describe.
Examples are: agreeable, obedient, proud, calm, careful, cruel, difficult, happy, troublesome, disruptive, obnoxious, good, friendly, impatient, rude, shy, unkind, suspicious, vain, envious etc.
When adjectives are dynamic (or used that way), it is appropriate to use them with progressive tense forms and in the imperative:

  • She's being rather disruptive
  • Don't be so vain
  • Be helpful
  • The girl is being unkind
  • The car is becoming troublesome
  • The children are being very good

They describe a quality which can be varied by the noun it refers to and is open to subjective rating.  The nouns with which they collocate are generally animate because we do not perceive inanimate objects acting on themselves.
Occasionally, inanimate subjects may be used but generally as something called a pathetic fallacy.  An example is
    The weather is being disruptive
in which the speaker is imposing a human attribute on an inanimate noun.  The example above of the car is becoming troublesome is another pathetic fallacy.  Cars and other machines do not intend to be troublesome or unreliable although it may seem that way.
The list will, therefore, include many adjectives which describe personality or behaviour.

With a slight change in meaning, many adjectives in this list can be used both statively and dynamically.  For example:

  • The program is unhelpful (stative use)
    vs.
    The man is trying to be unhelpful
    (dynamic use)
  • He's a kind person (stative use)
    vs.
    Be kind!
    (dynamic use)
  • This is good cake (stative use)
    vs.
    The children are being unusually good
    (dynamic use)
  • This is a difficult issue (stative use)
    vs.
    He's being difficult
    (dynamic use)

The following are used dynamically (and many can also be used statively) but the list is not exhaustive.

agreeable
angry
awkward
bewildered
brave
calm
careful
clever
clumsy
cruel
disruptive
eager
embarrassed
faithful
fierce
foolish
friendly
gentle
good
grateful
grumpy
happy
helpful
impatient
jealous
kind
lazy
mysterious
nice
obedient
obnoxious
patient
proud
repulsive
rude
shy
silly
suspicious
thoughtless
uptight
vacuous
vain
witty
worried
zealous

Notes:
  1. Not all of these can conventionally be used with the progressive form of the verb.
    We can have
        He is being obedient
    and
        Be obedient!
    but not, arguably
        *He is being grateful
    because exhibiting gratitude is arguably a stative phenomenon although
        Be grateful!
    is acceptable in a way that
        *Be fat!
    is not.
    We can also have
        Don't be bewildered!
    but not
        *She is being bewildered
    because the sense of the adjective is that it is beyond the person's control and
        Don't be suspicious!
    but not
        *Be suspicious!
    or
        *They are being suspicious.
    In this case, these uses of the adjective depend on whether the person suspects something or is being suspected of something so:
        He looks suspicious
    can mean either that he is suspected or that he suspects but
        She is looking suspicious
    can only usually mean that she suspects something.
  2. Some of these, mostly the negative ones, only allow a negative imperative: angry, jealous, cruel, clumsy, repulsive, obnoxious etcWe can have, therefore:
        Don't be impatient
    and
        Don't be repulsive
    but
        ?Be impatient
    and
        ?Be repulsive
    are very unusual if not wrong.  (But note, Be afraid, be very afraid.)
  3. A few have quite subtle shades of meaning when used statively or dynamically.  For example:
        Don't be clever!
    or
        You are just being clever
    imply criticism of someone for being too sharp or showing off
    and
        The animal is fierce
    is a stative use but
        Don't be fierce!
    is a dynamic use reserved for people who, it is presumed, can control their behaviour in a way the animals do not.

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eggs

Predicative or Attributive?

An attributive adjective pre-modifies (or, more rarely post-modifies) the noun it describes.
For example:
    the lovely picture
    the huge population
    the deafening roar
    the people responsible
    the definition proper
etc.
A predicative adjective follows the noun, after a copular or causative verb, and can be either
a subject complement
    he is angry
    she looks tired
    the car is economical
where angry, tired and economical refer to the subjects of the clause (he, she, the car)
or an object complement
    you made him angry
    she called me stupid
where angry and stupid refer to the objects of the clause (him, me).

The verb used with subject-complement predicative adjectives need not be to be.  It can be any of a number of copular verbs such as seem, sound, appear, feel, look (like) etc.  (For more, see the guide to copular verbs on this site, linked in the list of related guides at the end.)

Predicative adjectives only can refer to a clause
    What you want is impossible
    Learning English is quite easy
    She thought what I said was idiotic
So, no, adjectives don't only modify nouns, they can also modify clauses providing the clause is nominalised (i.e., acting as a noun as the subject or object of a verb).
In English, we cannot use an attributive adjective to modify a clause, so,
    *Impossible what you want
is unacceptable.
That is not the case in all languages.

follow

Adjectives only used predicatively (after the noun)

There are two areas to consider here:

  1. The a-series adjectives
    These include the disyllabic adjectives beginning in a, hence the name, such as afraid, afloat, awake, asleep, alive, alone, ashamed, averse, aware etc.
    None of these adjectives can be used attributively so we cannot allow:
        *an asleep man
        *the afloat boat
    See below under too, enough and so for another small complication of the a-series of adjectives concerning their modification.
  2. Dynamic vs. stative use
    When adjectives are used dynamically, predicative position is used.  We have, therefore, a difference in meaning between these pairs:
        The rude girl in room 12
    which is a stative use because we imagine the girl is usually or always rude so the attributive adjective use is chosen
    vs.
        The girl in room 12 is being rude
    which implies that her behaviour is not permanent but under her control so the predicative use is the only available choice.
        The patient customers waited in line
    in which we assume the people were characteristically patient
    vs.
        The customers were being patient and waiting in line
    in which no characteristic behaviour is implied and the customers might suddenly decide to become impatient.

    In both cases, a stative adjective may be used predicatively, but not the other way around so
        The girl in room 12 is rude = The rude girl in room 12
    and
        The customers were patient = The patient customers
    are possible with no change in meaning.

    The rule is that stative adjective use can be both predicative and attributive but dynamic adjective use demands only the predicative form.

  3. Adjectives requiring complementation
    Some adjectives require an explicit or implicit complement and, for that reason, can only be used predicatively.  For example:
        The book is devoid of humour
    not
        *The devoid book

        The woman was content with the answer
    not
        *The content woman

    The students were inclined to cheat
    not
        *The inclined students

        The policy is tantamount to giving up completely
    not
        *The tantamount policy
    etc.
  4. Pseudo-copular verbs
    Pseudo-copular verbs is the name sometimes given to verbs like feel, seem, become, grow etc. which perform a similar function to the copular verb be in linking the subject and an attribute.  With these, predicative use is the only possible structure:
        The woman feels ill
    is not the same as:
        The ill woman

        The garden became overgrown
    is not the same as
        The overgrown garden

        The manager grew angrier
    is not the same as
        The angrier manager
    etc.
in front of

Adjectives only used attributively (before the noun)

  1. Intensifiers: amplifiers, downtoners and limiters
    Intensifiers enhance, limit or reduce.  The most common adjective intensifiers are:
    Intensifiers Limiters
    entire
    complete
    perfect
    outright
    pure
    utter
    main
    only
    same
    precise
    We can't use them predicatively.  We can have, for example:
        The main reason
        The utter madman
        The outright idiocy
    etc.
    but not
        *The reason is main
        *The madman was utter
        *The idiocy was outright
  2. Non-intensifying, non-limiting meanings
    Some of these adjectives have non-intensifying meanings and can be used predicatively.  Compare, for example:
        His work was complete
    (non-intensifying use)
    or
        The complete works of Shakespeare
    (non-intensifying use)
    with
        The complete fool
    (intensifying use)
    but not:
        *The fool is complete
    and
        The measurement was precise
    (non-limiting use)
    or
        The precise measurement was 6.246mm
    (non-limiting use)
    with
        The precise reason
    (limiting use)
    but not:
        *The reason is precise

    The rule is that adjectives used as intensifiers or limiters can't be predicative.

    See the guide to intensifying adjectives linked in the list of related guides at the end for more.
  3. Noun-derived adjectives
        biological laboratory
        chemical plant
        nuclear power station
        countryside authority
    etc.
  4. Archaic participles
        a sunken ship
        a drunken party
        a shrunken head
        a stricken look
        a graven image
        a woven carpet
        a cloven hoof
  5. Adjectives derived from or close in meaning to adverbs
        an indoor event
        an outside door
        the upstairs windows
        an uptown area

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inherent

Inherent and non-inherent qualities

Most adjectives describe a particular quality of a noun.  For example, a blue car tells us about the car.  What we mean here is that blue is an inherent quality of the car itself.  However, a few adjectives can be used non-inherently.  Consider for example:

  • He's an old friend (non-inherent)
    vs.
    He's an old man
    (inherent)
  • She's a small businesswoman (non-inherent)
    vs.
    She's a small woman (inherent)
  • He's a heavy drinker (non-inherent)
    vs.
    He's a heavy man (inherent)

In the first of these examples, it is not the noun itself that is old, small or heavy; it is what we associate with the noun which carries the quality.  In these cases, it is the friendship, the business or the drinking which is old, small or heavy.  That's non-inherent use.
Note the use of new in, e.g., a new acquaintance (and the difference between that and my friend is old and the student is new).  This is because the adjective is not referring directly to the friend or acquaintance but to the friendship and acquaintanceship.  It's non-inherent.

old friends

Assumptions

old friends  

When there is a choice of understanding inherent or non-inherent meaning, the hearer's assumption in English will vary depending on the adjective use.

attributive adjectives
will be understood to apply non-inherently.  So,
    He's a light sleeper
    She's a small shopkeeper
    Mary's an old friend
will all be understood that it is the sleep, the shop and the friendship which are light, small and old respectively, not the people.
predicative adjectives
will be more rarely encountered in this respect but when they are, the understanding will be the inherent meaning.  So,
    The businessman is big
    My friend is old
    The shopkeeper is small
will be understood to refer to the people, not the business, the friendship or the shop.
post-positioned adjectives
often imply a non-inherent property (because they are also attributive).  For example:
    The person responsible for the mess [temporarily guilty]
    The responsible authorities [a permanent, inherent characteristic]
    A responsible person [a permanent, inherent characteristic]
There is a little more on this in the section of this guide on post-positioning of adjectives.

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flower

Adjective complementation

The verb complement means to improve by adding extra features of information and adjectives are prone to complementation by their nature.  For example, these expressions evince questions requiring the adjective to be complemented in the absence of a context:
    He is different (from what?)
    She was reluctant (to do what?)
    They are unsure (about what?)
    We are uncertain (about what?)
and can be complemented to make things clear.  For example:
    He is different from his brother
    She was reluctant to stay
    They are unsure whether they will stay together
    We are uncertain where to start
These examples show the four main ways in which predicative adjectives are usually complemented.  As we shall see, attributive adjectives can also be complemented, but rather differently.


deserted

Complementation with predicative adjective uses

Apart from me, the beach was deserted  

auroch

Adjective + prepositional phrase complementation

She is unafraid of the animal  

Many adjectives, especially those derived from prepositional verbs, are routinely complemented by prepositional phrases.
For example:

He's good at baseball The web site is accessible to members only
He is capable of anything She was deaf to his requests
I'm used to getting up early Shut is synonymous with closed
He's liable to a prison sentence / for the costs We are anxious about the costs
He's eligible for election I'm familiar with the argument
I'm due for a holiday She is dependent on his good will
I'm eager for the challenge That comment is not consistent with our policies
He's guilty of theft This is free from additives
That's inferior / superior to the old one He did it heedless of the consequences
The film is popular with children She came in oblivious of the danger
It isn't suitable for children They are responsible for the damage
In addition, the formulations of be + participle adjective + prepositional phrase form learnable chunks of language:
They were amazed at the weather I'm not interested in grammar
They were vexed at their bad luck I'm surprised at his indifference
I'm unacquainted with the class It is comprised of three sections
I'm delighted with the place She was delighted with her new job
I'm opposed to hunting The referee was prejudiced against the team
I'm prepared for anything He is not suited to this work
In many cases, especially with verbs of sensation of feelings, a parallel passive form exists.  For example:
surprised by, amazed by, vexed by, delighted by.
with others, only the passive by structure is possible:
characterised by, affected by

Some adjectives require complementation by a prepositional phrase.  For example:

They are averse to risks
She is answerable for the damage
I am content with my lot
This is devoid of sense
I am indebted to you
They are prone to errors
The contract is subject to your approval
That is tantamount to idiocy
And all these adjectives may only be used predicatively.

There are seven prepositions which frequently for phrases complementing adjectives.  Here are some examples of all of them:

about
He was angry about the damage
I was happy about the quality
She is worried about the result

Other adjectives often followed by about include: glad, knowledgeable, mad, annoyed, pleased.
at
She is good at French
He's clever at twisting the argument
She's hopeless at sport

Other adjectives often followed by at include: alarmed, amused, terrible, awful, surprised, dreadful.
in
They were successful in their examinations
She is interested in astronomy
You are mistaken in your assumption

Other adjectives often followed by in include: experienced, justified, persistent, unsuccessful.
of
I am afraid of snakes
We are fond of France
He is tired of the book

Other adjectives often followed by of include: certain, conscious, aware, glad, scared, terrified.
on
It is dependent on his agreement
I am keen on fishing
We are reliant on the money

Other adjective often followed by on include: intent, severe, based, set.
The preposition upon is more formal in many circumstances and not possible for some adjectives so we allow, e.g.:
It is dependent upon the weather
She is reliant upon her parents

but not
*I am keen upon chess
Using on is always secure.
to
She is answerable to the manager
I'm inclined to the cheaper hotel
He is liable to a fine

Other adjectives often followed by to include: opposed, averse, subject.
The preposition to is actually quite rare in adjective complementing phrases and should not be confused with the use of the to-infinitive (see above)
with
This is not compatible with the policy
I am familiar with the problem
They are impatient with incompetence

Other adjectives often followed by with include: angry, busy, comfortable, furious, sick, uneasy, unhappy, annoyed, bored, delighted, obsessed, pleased, satisfied.
handshake

Adjective + to-infinitive

Pleased to meet you  

Almost all predicative adjectives can be followed by the to-infinitive.  Examples of the form will suffice here:

The hotel was hard to find
They were thrilled to discover how much
They are certain to go
He is not likely to win again
Her excuse was difficult to believe
I am apt to forget things these days
The woman was slow to take offence
He was quick to respond

Again, a few adjectives actually require complementation by a to-infinitive.  For example:

The machine is inclined to be noisy She is bound to come to your party They were loath to complain too much
And, again, these adjectives may only be used predicatively.

delighted

Adjective + nominalised clause

I'm delighted that you came  

This structure is virtually confined to adjectives describing reactions and feelings or opinions.
It is also slightly less common than the simpler adjective + to-infinitive that is considered above.
These complements are generally formed with a that-clause or a contingent clause.  The words that, if and whether can often omitted.  Examples are:

The crowd were thrilled (that) he scored
I sure (that) she will know the answer
They are certain (that) she will arrive
She was unhappy (that) he didn't agree
I am not sure (if) they will be here in time
Her boss was incensed (that) she left early
I am happy (that) you believe me
The woman was amazed (that) he walked all the way
He was content (that) the work would be done
I am uncertain (whether) I can help

Usually, this type of complementation is a clause in the indicative as above but two other clause types are possible and both are much more formal, and rarer.

subjunctive
She is determined that he be here
I was unhappy that he be invited
putative should
I am very sorry that he should feel that way
We were mortified that she should be upset

A closely related form involves the use of a wh-clause as the nominalised clause.  Here the wh-word cannot be omitted and the adjectives are confined to speculation and opinion, almost to (un)sure and (un) certain, in fact.  For example

I'm not sure where the road goes
They were uncertain how many people would come
I was sure when the time had come
Her boss was unsure what was best to do
I wasn't certain which job would suit me best
She was certain which way to go

doors

Adjective + wh-word + to-infinitive

I'm not sure which one to open  

This is closely related to the last structure but involves a small additionally complication in that we add a to-infinitive.  As for the use of a wh-clause above, the use is confined to expressions of certainty, most typically with (un)sure and (un) certain.  For example:

I'm not sure where to go next
They were uncertain how many to take
I was sure when to move
on
Her boss was unsure what to do
I wasn't certain which job to take
She was certain who to ask


thirsty

Complementation with attributive adjective uses

Don't approach a thirsty lion  

Complementation with attributive adjectives is less common and usually slightly more formal.
There are two main forms and both involve splitting the complementation so the structure is:
    determiner + adjective + noun + complement

city

Attributive adjective + prepositional phrase

It's a beautiful city at night  

Adjectives used attributively may take prepositional phrase complementation.  For example:

This is a good spot for a picnic
It's lovely weather for walking
He's a good person in an emergency
It's a less pleasant walk in the rain
He is the best student at mathematics
He has a similar job to mine
She is a difficult person at work
He is a more difficult person in the morning

A structure which conforms to the same patterning concerns what are known as ordinal terms such as first, second, next last etc.  With these pseudo adjectives, both a prepositional phrase and the to-infinitive can form the complement.
For example:

This is the first item on the list
It's the last place to visit
It's another question to ask
He is the next man in the queue
That's the fifth time in a month
She is the first person to know

dare

Attributive adjective + to-infinitive

This is a hard place to get to  

Attributive adjectives may also take to-infinitive complementation.
For example:

This is a good place to stop
It's a peaceful area to live in
It's a cheaper car to run
He is the best person to ask
That's a silly reason to complain
She is a better person to work with

As the examples show, the formulation also allows comparative and superlative adjective forms to be used.  That is less common, but possible, with predicative adjective use.

queue

Ordinals

The next person in the queue  

A structure which conforms to the same patterning concerns what are known as ordinal terms such as first, second, next last etc.  With these pseudo adjectives, both a prepositional phrase and the to-infinitive can form the complement.
For example:

This is the first item on the list
It's the last place to visit
It's another question to ask
He is the next man in the queue
That's the fifth time in a month
She is the first person to know

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double

Double adjectives and compounds

Double adjectives and compound adjectives conform to the general rules for adjectives concerning inherent and non-inherent properties, stative and dynamic uses and much else.
There are, however, some issues to be aware of.
Compound adjectives are formed in four main ways:

  1. object or subject noun + verb (-ing or -ed)
        heart-stopping
        handmade
        car producing
        machine cut
  2. adverbial + verb
        offputting
        self-starting
        backsliding
        outgoing
  3. noun + adjective
        travelsick
        bone idle
        duty free
        olive green
  4. adjective + adjective
        bittersweet / bitter-sweet
        Franco-British
        grey-green
        Sino-Russian
    The first part of such compounds can contain a derived adjective which cannot usually stand alone.

Double adjectives, as opposed to compounds, are only of type 4. and are formed of two adjectives combining their senses to make a third meaning.

Because English is right headed, the right-hand word determines meaning and word class.  In all these cases, the right-hand part is an adjective (or a participle acting as one) so they are adjectives.
(Occasionally, but quite rarely, the right-headed rule is broken and the combination of an adjective and a noun or a noun and a noun results in a compound adjective.  For example,
    The place has old-world charm
    It's a road-safety problem
)

hyphen

Hyphenation

To hyphenate or not is often at the whim of the writer in English and opinions will differ, but there are some rules of thumb, however the adjectives are formed.

  1. Attributive double or compound adjectives are always hyphenated or written as one word.  But when they are not considered a single concept, the two adjectives are separated by a comma.  For example:
        the wooden-hulled boat (in which wooden only applies to the hull, not the boat)
        the green-shuttered house (in which the house has green shutters)
        the green, shuttered house (in which the house is green and closed up)
        the grey-green cliff (in which the cliff is neither grey nor green but a mix of the colours)
        an open-minded person (in which the adjective is a single concept meaning something like tolerant)
        an English-speaking country (in which English is spoken)
        an English, speaking clock (in which the clock speaks and is English in origin)
        an in-house project
        an out-of-school activity
        a breath-taking idea
  2. When used predicatively, hyphenation is often optional and sometimes unusual.  For example:
        The house was red roofed
        The boat was wooden hulled
        She is quite open minded
        Britain is mostly English speaking
  3. Some well-established compound adjectives are almost always hyphenated in both predicative and attributive uses.  Occasionally, a compound has become so common that it can be written as a single word (but automatic spell-checkers will differ).  For example:
        The idea was breathtaking
        The children were spellbound

        the inbound ferry
        an open-door policy
        The technology is cutting-edge
        The food is ready-to-eat
        The coat was bought off-the-peg
    but even the hyphenated ones frequently appear without the hyphen.
  4. When two or more predicative adjectives are not used as a single concept they imply two unconnected attributes of the noun.  They are joined with a conjunction so we get, for example:
        They came home tired, wet but happy
        He was delighted and touched
        They were happy as well as rich

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marked

Markedness

Consider these questions and why they sound somewhat odd.  Then click here for an explanation.

  • How young is Mary?
  • How bad is the food in the restaurant?
  • How impermanent is the ink?
  • How small is the house?
  • How incomprehensible was his talk?
  • How short is the boy?
  • How unfair was the pay rise?
  • How dishonest was his excuse?
  • How dim was the light?

In English, many adjective pairs come as a marked and unmarked forms.
The unmarked forms above are:
    old
not young
    good
not bad
    permanent
not temporary
    large
not small
    comprehensible
not incomprehensible
    tall,
not short
    fair
not unfair
    honest
not dishonest
    long
not short
    bright
not dim
etc.
Any form which has a negative prefix or suffix will usually be the marked form.  So all of these are marked: impatient, unpleasant, displeasing, hopeless.

Markedness also applies to nouns and to some extent determines the adjective that it is appropriate to use with them.
So, while it is in order to have, for example:
    a female dog
    a female actor
    a female pig
    a male nurse
    a useful kitchenette
    a cute kitten
etc.
it is either less common, doubtful or simply wrong to have:
    *a female bitch
    *a male sow
    ?a female nurse
    ?a huge kitchenette
    *an old kitten
etc.
The fact that the language is sexist in this respect may be regrettable but happens to be historically determined.  Nouns marked for sex are, it is true, slowly disappearing from the language but they persist in, e.g., names for animals (lioness, hen, bull, gander etc.) and in some titles (duke, duchess, king, queen etc.).

How unsafe is it to assume that this will happen the same way in your learners' languages?
Very.

For more on markedness, see the guide linked in the list of related guides at the end.

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hammer

Proleptic uses of adjectives

hammer it repeatedly
hammer it flat
 

Proleptic means, roughly speaking, 'anticipatory' and this use allows an adjective where English would normally expect an adverbial because, on the face of things, the word is used to modify a verb rather than a noun phrase.  Proleptic use implies that we are considering the end effect, not the current action.

In the example above, we have both uses:
    Hammer it repeatedly
is the 'normal' use of a verb post-modified by an adverbial of some sort (in this case, the adverb repeatedly) and we can also have, for example:
    Play it loudly
    Cook it until done
    Do it quickly but carefully
    Roll it evenly
and all the adverbials in black refer to the verb phrase.
However, with
    Hammer it flat
we have the verb phrase followed by the simple adjective and we can also have, for example:
    Make it wet
    Play it loud
    Pull it straight
    Roll it smooth
    Pull it tight
all of which appear to be 'wrong' because we seem to be using an adjective to modify a verb and, in English, that is not permitted.  They are, however, perfectly acceptable.
What is happening here is that we are anticipating the condition of the object itself rather than referring to the way the action should be carried out so we are modifying the noun or pronoun, not the verb, and that is the central role of adjectives, of course.

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acting

Adjectives derived from nouns and adjectives acting as nouns

Adjectives derived from nouns are called denominal adjectives.
Adjectives acting as nouns are called nominal adjectives.

concrete

Denominal adjectives

concrete blocks  

There are three issues to consider with adjectives derived from (or converted from) nouns:

  1. Some denominal adjectives, often applying to particular professions or services, can only be used attributively so we have, e.g.:
        the civil law (not the law is civil)
        a law practice (not the practice is law)
        an emergency service (not the service is emergency)
        a medical school (not the school is medical)
    etc.
  2. A few, often referring to the materials, such as concrete can occur in both positions, so we can have
        a concrete wall
        a wooden house
        a silk shirt
    etc.
    and, less commonly
        the wall is concrete
        the house is wooden
        the shirt is silk
  3. Denominal adjectives are often defined as invariable because some can be used both attributively and predicatively (i.e., the act like 'normal' adjectives) but they cannot be used comparatively or superlatively.  This is because they have more in common with classifiers (see below) than with true adjectives or epithets.
    We can have, therefore:
        the tin roof
    and
        the roof is tin
    but not
        *the tinnest roof
    or
        *the roof is less tin

It is often tempting to imagine that something like a crime novel is an example of a noun becoming an adjective.  In fact, both adjectives proper and nouns can pre-modify nouns without a magical change in word class.
Compare these:

Set 1 Set 2
the village pump a remote village
a garden wall a high wall
a love song a touching song
winter storms freezing weather

Set 1 comprises nouns used as modifiers of other nouns.  Set 2 comprises adjectives modifying nouns.  How do you tell?
Think for a minute and then click here.
old young

Nominal adjectives

the old and the young  

When adjectives act as nouns, they are often slightly formal.  Examples include
    The old need to be respected
    The young are always too impetuous
    The meek shall inherit the earth
    Only the foolish would do such a thing
    The wise would never contemplate it
    The unmarried often have more to worry about
    That's OK for the well paid but what about the underpaid?
etc.  All of the above are plural in terms of concord with the verb.  We cannot have, for example:
    *the young is
    *the old is
etc.
A small class of adjectives can form singular nouns.  Example include:
    The accused stood before the court (also plural)
    The deceased was known to us all
    He risked voting for an unknown
    She is the first to arrive and the last to leave

etc.

A significant sub-class of these adjectives are the nouns for nationality derived from them
    the French
    the English
    the Dutch
    the Japanese
etc.
but many nationalities are referred to by plural nouns
    the Germans
    the Greeks
    the Americans
etc.
The system is irregular but the majority fall into the first category.

English allows adjectives to act as nouns (with the definite article usually) as we saw above and modification is possible as in, e.g.:
    the filthy rich
    the very wise
    the extremely ill
    the perfidious English
etc.
These are generally attributive in terms of word order because attempts to use them predicatively may result in, e.g.
    the rich are filthy
which is unlikely to be true and not at all what is meant.

Abstract concepts can also be nominalised from the parallel adjective so we see, for example:
    She went from the sublime to the ridiculous
    Think the unthinkable
    The worst is yet to come
    Hope for the best
    He came away with a silver although she was hoping for a gold

Adjectives which are only used predicatively, such as the a-series, and adjectives which are dynamic in use do not form nouns.  We cannot derive
    *the aware
from
    they are aware
or
    *the rude
from
    the customers were being rude

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ordering

Post-positioned attributive adjectives

Attributive adjectives in English usually come before the noun but there are exceptions (called postpositive or postposed adjectives).  Even when an adjective follows the noun, it may still be an attributive use because there is no connecting verb to link the ideas.

  1. After pronouns ending in -one, -thing and -body we always have postposed adjectives.  So we have
        anything useful
        somebody nice
        anyone present
    etc.
  2. The same occurs with the demonstrative pronoun, those, e.g.
        those accountable
    but not with that, this or these, which can also be demonstrative pronouns.
  3. There are two common adjectives which usually follow the noun.  E.g.
        the chairperson elect
        the holiday proper
  4. Some compounds (often old-fashioned or rare ones) also show this word order.  E.g.
        court martial
        heir apparent
        attorney general
        princess royal
    Some of these forms are borrowings from French in which the French word order is retained.  Others are produced by restaurants wishing to appear sophisticated such as:
        apple charlotte
        peach Melba

        pommes grecques
    and so on.
  5. A few adjectives can vary in meaning depending on whether they precede or follow the noun:
        The people involved in the accident
    refers to fact that the people were in the accident, but
        It was an involved explanation for the accident
    refers to the fact that the explanation was complex.

        The police officer concerned took statements from everyone
    refers to the police officer who was dealing with the accident, but
        The concerned police officer took statements from everyone
    refers to the fact that the police officer was worried in some way.

        the students present
    refers only to the student who are here, but
        the present students
    refers to everyone who is currently a student.

        The course proper starts on Thursday
    refers to the course accurately described
        It's a proper course
    refers to the course being well designed and fir for its purpose.

    It may be helpful to consider some of these as examples of reduced relative clauses
        the people [who were] involved
        the police officer [who was] concerned
        the students [who are] present
    etc.
    In the second case, however, ambiguity is created concerning whether the police officer was doing his/her job or whether the police officer was worried about something (or, just possibly, both).
  6. In some related cases, placing the adjective before the noun refers to a temporary condition but placing it after the noun refers to a permanent state (i.e., inherent and non-inherent properties).  For example:
        The available money [all of it] is adequate
    vs.
        The money available now [some of it] is adequate

        The visible galaxies [all of them]
    vs.
        The galaxies visible tonight [some of them]

        We need a responsible person to do this [a permanent characteristic of the person]
    vs.
        This is the person responsible for doing this [a temporary duty or guilt]
  7. Adjectives formed from verbs are sometimes found in post-position.  We saw this with concerned and involved above where the meaning of the adjective is altered depending on whether it precedes or follows the noun.
    Other verbal adjectives also follow this pattern with no change in meaning and cannot come before the noun.  For example:
        The people arrested were taken to the police station
    (Not: *The arrested people)
        The customers objecting to the increase all wrote to the manager
    (Not:*The objecting customers)
    However, it is here more arguable that this phenomenon is a reduced relative clause as both the examples can be re-expressed conventionally as:
        The people who were arrested were taken to the police station
        The customers who were objecting to the increase all wrote to the manager
  8. Adjectives related to measurement always take post-position, so, for example:
        It's two feet long
        It's five metres square
        The play is an hour long
        The road is 15 feet wide
        The water was three metres deep

        The wall was only a foot high
        The child is only 5 years old but already 3 feet tall
    etc.
    Oddly, no adjective in English exists for weight in this way so we resort to the prepositional phrase, e.g.:
        It's four tonnes in weight.
  9. Two adjectives – aplenty and galore – always follow the noun.  (The latter, perhaps, because that's the conventional ordering in Irish, whence the word comes.)  Neither can be used predicatively:
        We have food aplenty and drink galore
        *The food is aplenty and the drink is galore

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crane

Modification with too, enough and so

too heavy or not heavy enough  
  1. Predicative use only
    When these modifiers are used, the adjective they modify can only be used predicatively.
    The modifier enough follows the adjective but so and too precede it.
    We can have
        If the learners are hardworking enough, they will pass
    that's a normal predicative use
    but when used attributively, it's not possible to include enough.  You can't have
        *Hardworking enough learners will pass
    but deleting the modifier makes an acceptable sentence.
    Similarly, we can allow:
        The man was so stupid he didn't understand a simple instruction
    but not the attributive use as in
        *The so stupid man didn't understand a simple instruction
    or
        The game was too easy
    but not
        *It was a too easy game
  2. The a-series of adjectives are not usually modified with too, enough and so.  Therefore,
        *She is awake enough
        *The boat was so afloat
    or
        *They are too alone
    are not acceptable
    although
        She is too ashamed to speak
    and
        He was too afraid to ask
    are fine.
    The modifier so is usable with some in the a-series so we can have
        She is so afraid of the dentist that she won't go
    but this is not reliable as, e.g.:
        *They are so asleep
    is not acceptable.
    The preferred (and safest) modifier with the a-series is either very much as in, e.g.:
        I am very much afraid that is not going to be possible
    or a modifier adverb unique to the word such as:
        She is sound asleep
        They are wide awake
        I was fast asleep
        The ship was hard aground

For considerations of modification of adjectives with fairly, rather and quite, refer to the guide to adverb modifiers linked in the list of related guides at the end.

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classify

Epithets and classifiers

When nouns are used adjectivally, they are normally classifiers.  Classifiers are also sometimes called noun adjuncts but on this site, they usually aren't.  The difference between a classifier and an adjective proper (an epithet) is that classifiers can't normally be modified with intensifiers like very or absolutely, or with so, too and enough and do not have comparative or superlative forms.  You can't have, e.g.
    *a very village pump
    *an extremely brick wall
    *a so butterfly collection
    *a wooden enough house
    *the bricker house
    *the sportsest car
and so on.
There's a bit more about this in the guide to modification linked in the list at the end.

We noted above under denominal adjectives, that a word such as concrete can be used both predicatively and attributively and this indicates that it is sometimes difficult (but rarely necessary) to distinguish between a denominal adjective and a noun modifier.
A simple test is to pose a How question.  We can ask, for example:
    How old is the car?

and hence old qualifies as an adjective, but we cannot ask:
    How saloon is the car?
because saloon is a classifier, not an adjective.
For more, see the guide to classifiers and partitives on this site, linked in the list at the end.

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3

Gradability

Classifiers, as we saw, are normally ungradable.  However, some central adjectives are also rarely made gradable and the normal way to analyse the issue is to identify three basic classes of ungradable adjectives:

  1. Those whose meaning is in some way absolute.
    These include words such as ultimate, total, entire, unique, absolute, utter, perfect where it is logically impossible to conceive of a grade.  Terms like *more unique, *very perfect and so on are, therefore, often considered wrong although you will find plenty of examples of their use: more average, less unique, most complete, more extreme, more total etc.  Or even:
    most unique
    What one is prepared to accept is often a matter of formality and personal preference.
  2. Words which refer to a specific on-off quality.  These are usually adjectives or near classifiers such as metal, pregnant, unlocked, French, fatal, just etc.  The reason these are not gradable is that one is either pregnant or not, something is either metal or it isn't, locked or unlocked and a wound is either fatal or not (there's no intermediate stage).  Again, this is often a rule flouted in colloquial speech and terms such as She's very French to refer to an attitude rather than a nationality are common.  We can also have less full, half empty and so on but not *very empty although very full is heard.
    In the Daily Telegraph (a British national newspaper), we find, e.g.:
        We're just very grateful that he's survived this incident because it could have turned out to be quite fatal
        (The Daily Telegraph website)

    Perhaps the speaker meant quite dangerous.
  3. Words which in themselves include the concept of very or extremely.  It is often averred (and it is often told to learners) that some 'extreme' adjectives can only be modified with words like utterly, completely, really, extremely, exceptionally, awfully, exceedingly, especially, dreadfully, extraordinarily, enormously, fantastically, vastly etc.  The commonest lists include items such as:
    Gradable form Ungradable form
    hot boiling
    cold freezing
    beautiful stunning
    surprising amazing
    good wonderful
    bad awful
    rude obnoxious
    nice delicious
    and so on.

However, the rule is not fully reliable and one might hear or read, for example:
    That's very delicious
    That's even more stunning
    It's very awful
    That's incredibly nice

etc.  The last of these examples is a contested use of the adverb incredibly which has come to mean, in common, casual speech among some groups something akin to very.
Such uses should be handled with care, however, because they are idiomatic and unpredictable so, for example, few would accept:
    ?She's very wonderful
    ?That's a bit amazing

and these uses would certainly be deprecated in formal speech and writing.

There is a separate guide to gradability which also includes consideration of adverbs linked from the list of related guides at the end.

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sunken

Participle adjectives

a sunken boat  

We can distinguish two types of participle adjectives in English, both of which can almost always be used attributively and predicatively.

Adjectives formed from the present or progressive participle.  For example:
He was an interesting man
The outcome was very surprising
That's a fascinating result
They told a gripping tale
Adjectives formed from the past participle.  For example:
There was a broken window in the first floor
The children were delighted to see her
She seemed uninterested in the result
The terrified people ran out into the street

The general rule is that -ing adjectives refer to what a thing or a person is and -ed adjectives refer to how someone feels.

We can refer to what something was (the flight was frightening) or to how someone felt (I was frightened).

This is an important area because many languages do not form adjectives in this way (or have other ways of deriving them from verbs) and much confusion and bewilderment is caused.
The usual errors are misunderstanding what is being described so, for example, saying
    She is boring
instead of
    She is bored
and so on, but there are other consequences of language differences which result in errors such as
    *They are very irritating me
    *I am welcomed by her
etc.
Partly, the cause is that English does not distinguish morphologically or phonetically between a word acting as a verb and one acting as an adjective.  Both forms take either -ing or -ed (or are irregular, usually in the same way).
Most languages do not have this ambiguity of form and the hearer / reader can immediately recognise whether a word is adjectival or verbal in use by the morphology or pronunciation, and usually both.

Here are some examples of the difficulties thrown up by the failure in English to distinguish between verbs and adjectives in the forms of words.

a drunken party The past participle of drunk is no longer drunken but the form is maintained in the adjective.
There are a few older English forms which survive as adjectives only and they include: drunken, sunken, shaven, shrunken, learned, blessed, beloved, crooked, dogged, ragged.  For example:
    He shaved his head
    The man with the shaven head
    The boat has sunk
    The sunken boat
etc.
In the last six cases, the adjective retains the earlier syllabic pronunciation of -ed as /lɜːnɪd/, /blesɪd/, /bɪ.ˈlʌ.vɪd/ /krʊkɪd/, /dɒɡɪd/ and /ræɡɪd/ rather than /lɜːnd/, /blest/, /bɪ.ˈlʌvd/, /krʊkt/, /dɒɡd/ and /ræɡd/ which are how the past participles of the verbs are pronounced.
One oddity is the adjective aged which is pronounced /eɪdʒd/ when it refers to something which has matured or reached a certain age as in, e.g.:
    An aged wine is more acceptable
and
    Aged 14 he left school
but it retains the older pronunciation of /ˈeɪdʒɪd/ when it means elderly as in, e.g.:
    He had an aged servant
or
    The dog was a little aged and short sighted.
he was offended by my father Is this a passive verb form or an adjective?  Can we say
He was very offended by my father?
Yes?  Then it's an adjective.  No?  Then it's a passive.
The distinction is whether the clause answers the question Who offended him? or whether it answers the question How did he feel?
In the first case, the word is a passive participle:
   
Q: Who offended him?
   
A: He was offended by my father.
In the second case, the word is an adjective:
    Q: Why was he angry?
   
A: Because he was very offended by my father.
the manager was relieved Meaning 1: he felt relief (relieved is an adjective and we can use very before it)
Meaning 2: the manager was replaced by someone else (relieved is the verb; it's not possible to insert very)
the players were not downhearted If this is a participle, what's the present tense of the verb?
(Answer: it is an 18th century figurative use derived from the Old English hiertan, meaning give heart to.  The Modern English is hearten and thence we can derive heartened, a passive participle meaning encouraged.)
the escaped leopard This is a participle adjective but it can't be used predicatively: *The leopard is escaped because it is verbal rather than adjectival in nature.  The subject of the verb is the leopard.
she is very self-centred
the extremely self-centred man
This looks like an ordinary participle adjective until we realise that there is no corresponding verb, to self-centre.
The same applies to some others such as talented, unconcerned, flabbergasted, renowned etc.
These are adjectives for the simple reason that we know that they can't be anything else because there is no verb.

choice

Participle adjective or verb?

Judging whether a word is adjectival in nature or whether it is a passive or progressive use of the verb is not always easy.
It is, nevertheless quite important because other languages deal with the issue very differently and that results in considerable inter-language error as we saw above.

The first question to ask is whether there actually is a verb to which we can refer.  Is the word derived from a Modern English verb at all?
If it isn't, the word is acting adjectivally.  So, for example,
    The accusation was unfounded
is adjectival because there is no verb to unfound.
    They are talented children
is also adjectival because there is no verb to talent and
    He is a gifted pianist
is adjectival, too.
Many compound adjectives work this way so we get, for example:
    This is a fruit-based drink
(with no verb to fruit-base)
    It's a mineral-derived oil
(with no verb to mineral-derive)
and this also works with the -ing adjectives as a test so we have, for example:
    a side-splitting performance
(with no verb to side-split)
    a fact-finding mission
(with no verb to fact-find)

How do we know which is which?

  1. For -ing forms, there are three usual tests:
    1. Try modification with very or another intensifying adverbial.  So we have, e.g.:
          The film is extremely frightening
      (adjectival use)
      vs.
          *The film is extremely frightening me
      (unacceptable because it's the verbal use)
    2. Locate a direct object.  So we can have, e.g.:
          That's an exceptionally irritating noise (adjectival use)
      vs.
          *That noise is exceptionally irritating me
      (unacceptable because it's the verbal use)
    3. See if it is possible to change to the simple aspect of the verb tense.  So, e.g.:
          That's very rewarding work
      (adjectival use)
      vs.
          *The work rewards
      (not acceptable so not a verbal use)
  2. For -ed forms, the tests are more difficult to apply.
    1. Occasionally, it is obvious that we are dealing with an adjective rather than a verb simply because there is no verb available (although the adjective looks like an -ed participle).  For example:
          She was unimpressed by his behaviour
          They were uninterested in my problems
      must both be adjectival because we cannot have:
          *His behaviour unimpressed her
          *My problems uninterested them

      Unfortunately, these are quite rare examples.
    2. We can apply the modifier test so we can see that, e.g.:
          The house was very destroyed
      is not possible so it must be the verbal use of the word.
      However, modifiers can be applied to verbs as well so,
          The house was completely destroyed by the earthquake
          She was very embarrassed by his language
      are both possible although the use is clearly verbal (shown by the use of the agentive by-phrase) and the test breaks down.
    3. A more reliable test is to try inserting a that-clause or other clausal complement and then the distinction is clear:
          He was disappointed that the money did not arrive
      (adjectival use)
          *He was disappointed by the money did not arrive
      (not possible with a verbal use)
          I was persuaded by his argument
      (verbal use)
          I was persuaded that he was right
      (adjectival use)
          She was absolutely delighted to hear that she has passed
      (adjectival use)
          She was absolutely delighted by the result
      (verbal use)
    4. A further test is to replace the copular verb be with another copular verb.  Only the verb be naturally forms passive (i.e., verbal) uses so in, e.g.
          Mary was depressed
      we can make the active form
          The news depressed Mary
      but in
          Mary seemed depressed
          She became frightened
      or
          They appeared interested
      no such active form is available so the uses of depressed, frightened and interested are adjectival.
    5. A final test is to try modifying the word with too or very.  This is possible if the word is adjectival, unlikely or downright impossible when the word is verbal.  For example:
          He is too disappointed to discuss it
          They are very tired
      are both adjectival so the modification is acceptable.
      However,
          *The road has been very repaired
          *The house is too painted for my taste

      are both verbal so the modification is unacceptable.

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ordering

Adjective order

When there is more than one adjective modifying a noun, there is a conventional ordering.  Much tosh is devoted to this area, not least in coursebooks (possibly because it's easier to write exercises for the area than to demonstrate its communicative value).

Insert these adjectives into the gap in this sentence between the and lorry:
Greek, huge, old, shabby, green, Volvo

The _________________________________________ lorry was parked outside.
Click here when you have done that.


and and but

Coordinating adjectives

An error frequently made by learners is to misuse coordinators between adjectives, producing unnatural or plain wrong syntax such as:
    *It was a pretty and little village
    ?It was cheap and good
The cause of these errors is that the learner is unaware of the rules in English, probably because they have never had them pointed out, merely having been corrected.

The rules are:

  1. For the coordinator and:
    1. We can put and between adjectives (but often don't) only if the adjectives describe the same sort of property.  This means, in effect that the adjectives have to occupy the same column in the table above.  So, we allow, for example:
          An attractive and photogenic village
          A large and cumbersome package
          An interesting and original idea

      but not:
          *A wide and polluted river
          *An interesting and small village
          *A silly and new idea
    2. If the adjectives are not descriptive of the same kind of attribute, we prefer separation with a comma:
          A wide, polluted river
          An interesting, small village
          A silly, new idea
    3. The insertion of adverbials to distinguish one or other of the adjectives is common in coordinated and-phrases and this overrules the first principle that the adjectives must describe the same property.  So, we may have, for example:
          An interesting, cheap holiday
      but not
          *An interesting and cheap holiday
      in the normal way but may choose to insert the coordinator when one adjective is particularly marked, as in:
          An interesting and surprisingly cheap holiday
      and that is acceptable.
    4. Predicative use allows the coordinator and more frequently so we may have:
          A beautiful old rowing boat
      and not allow
          *A beautiful and old rowing boat
      but tolerate
          The boat was old and beautiful
      in which the normal adjective ordering is reversed for effect (see below).
  2. With the use of but as a coordinator, the situation becomes slightly more complex and there are also sub-rules to consider:
    1. If the adjectives are contrasting, we use but between them so we allow:
          A small but varied selection
          A large but manageable package

          An inexpensive but effective procedure
    2. If we choose to use two contrasting adjectives, the comma separation is not usually acceptable:
          *A tiny, populous town
          *An enormous, light book
          ?An inexpensive, effective procedure
    3. Even when there is ostensibly no contrast, the speaker / writer can insert one to mark the phrase.  So, we might have:
          An elegantly dressed, old English man
      in which the adjectives are ordered conventionally but which can be marked for contrast as:
          An old but elegantly dressed English man
  3. A confusing aspect of coordinated adjectives, especially when the coordinator is but, is that the normal ordering is often reversed.  We can have for example:
        A handsome, old car
    in which, as expected, the subjective attitude adjective (handsome) comes before the more objective one (old).
    However, if we choose to contrast the adjectives with but, the order is usually:
        An old but handsome car
    not
        *A handsome but old car
  4. The forms can be combined.  We may have a complex adjectival phrase such as:
        It was an interesting and surprisingly cheap holiday but greatly entertaining
    in which we have used both coordinators in a predicative adjectival phrase.
    We would not normally allow the attributive use of complex adjectival phrases so:
        An interesting and surprisingly cheap but greatly entertaining holiday
    would not usually be acceptable stylistically.

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comparative

Comparative and superlative forms

There are two ways to make comparatives and superlatives of adjectives:

inflexion
adding -er or -est to the adjective as in, e.g.:
    black > blacker > blackest
periphrasis
using more and most or less and least as in e.g.:
    interesting > more interesting > most interesting
    attractive > less attractive > least attractive

It is often said that:

  1. monosyllabic and disyllabic adjectives form the comparative and superlative by inflexion with -er and -est.  So we get, e.g.:
        old > older > oldest
        small > smaller > smallest
        happy > happier > happiest
        bitter > bitterer > bitterest

    and so on.
  2. Adjectives with three or more syllables take the periphrastic form with more and most or less and least, so we get, e.g.:
        conventional > more conventional > most conventional
        traditional > less traditional > least traditional
        uncaring > more uncaring > most uncaring

        complicated > less complicated > least complicated
    and so on.
  3. Superlative forms require the insertion of the definite article, the.
        the coldest, the most beautiful
    etc.
  4. The superlative forms should not be used when comparing two nouns.  So, we are admonished:
        He is the better of the two
    is correct, but
        She is the oldest of his two children
    is wrong.
    We shall see.

As far as it goes the first two rules work but they soon break down, unfortunately, and getting learners to rely on them is often a source of teacher-induced error.
In reality, life is more complicated.

soaked

It is possible to use periphrastic forms with all adjectives

even more wet  

Especially when use predicatively, all adjectives can use the periphrastic form regardless of the syllable count.
For example:
    Donald Trump is wealthy but Bill Gates is more wealthy
Even monosyllabic adjectives can take the periphrastic forms, especially when they are used in conjunction with longer adjectives so we hear, for example:
    The views were fabulous in the evening but more great in the morning.
    They were poverty stricken but their neighbour was even more poor.
    She was soaked before but is even more wet now.
When the modifier even is used, this becomes quite common (or even more common).

2

Issues with two-syllable (disyllabic) adjectives

With disyllabic adjectives, simply tacking on the inflexions will often work but there are numerous exceptions.
Here are some rules:

  • If the sound at the end of the adjective is an unstressed vowel (such as /i/, /l/ or /ə(r)/, then the inflexional change is most common:
        noisier, wealthier, chubbier, narrower, gentler, subtler, cleverer, maturer
    etc.
    To this list we can add some common disyllabic ones such as common, quiet etc.
    The periphrastic form is common with all of these.
  • With other disyllabic adjectives, mostly those ending in -ic, the periphrastic form is required:
        more basic, most comic, more pot-bound, most drastic
    etc.
  • Adjectives formed by suffixation with -ful, -ish, -ous, -al and -less always make the comparative and superlative forms periphrastically:
        more useful, less foolish, more hopeless, most joyous, more central
    etc.
    All adjectives formed with -able and -ible are at least trisyllabic so follow the same pattern.
  • No participle adjectives, however long or short, inflect.  We always have the periphrastic
    more tiring
    and most bored
    not the inflected
    *tiringer
    or *boredest.
  • It's also worth focusing your learners on the fact that the syllabic '-le' ending (/əl/) on words like simple changes to a non-syllabic /l/ when used in the comparative or superlative form (/ˈsɪm.pəl/, /ˈsɪm.plə/).
3

Issues with three- (and more) syllable adjectives

The rule that adjectives of three or more syllables always take the periphrastic form is also not absolute.
Adjectives formed with the prefix -un and the suffix -y, can take the inflected form although they are trisyllabic, so we get
    unhappy > unhappiest
    unholy > unholiest
    unlucky > unluckier
    unruly > unrulier
    untidy > untidier

With these, the periphrastic form is often preferred, in fact.
This does not occur with other endings so we have
    unchanging > more / most unchanging
    unpleasant > more / most unpleasant

etc.
where the rule is as above for disyllabic adjectives formed with suffixes.
Compound adjectives, despite often being at least trisyllabic, also break the rule and the first word takes the inflexion so we get, e.g.:
    low-paid > lower paid > lowest paid
    long-lasting > longer-lasting > longest-lasting

Oddballs
oddball
There's a group of common adjectives which form comparative and superlative forms from different roots:
good-better-best, bad-worse-worst, far-further/farther-furthest/farthest.
The word well is sometimes used adjectivally (to mean not ill) rather than adverbially and follows the same pattern.  It is arguable that the comparative of the adjective ill is worse.
The form of older commonly used in family relationships, elder-eldest, can only be used attributively (although it can be nominalised as the elder/eldest).
We can have, therefore,
    He is the elder brother
but not
    *His brother is elder
Additionally, older than is preferred to *elder than.
The derived adjective, elderly, has no such constraints.

friends

Determiners with superlatives

my oldest friend  

A source of teacher-induced error is assuming that all superlative forms must be preceded by the definite article.
That is often true but the real rule is that they must usually be preceded by a determiner, not necessarily that determiner.
We can have, therefore:
    He is the best in the class
    He is my oldest friend
    That was their most enjoyable holiday

etc.

We can also omit the determiner and have:
    Which one is best?
    Of all of them, she was keenest to go.

In these cases, inserting the definite article is not wrong but may sound somewhat formal.
With the periphrastic form, however, a determiner is almost always required because of the possible ambiguity with the meaning of most (= very, in some senses).  So, generally:
    She is the most intelligent
is preferred to
    She is most intelligent.
because that could mean she is the most intelligent or she is very intelligent.

wine

Two vs. more than two items to compare

which is best?  

The rule suggested above is often given that two items cannot be compared using the superlative so, following that we should believe that:
    I can bring red or white wine.  Which is best?
is wrong and it should be:
    I can bring red or white wine.  Which is better?
It is the case that the second of these is correct, albeit slightly formal to some people's ears.
It is also not arguable that the superlative form will conventionally be used for three or more items so:
    I can bring red, white or rosé.  Which is best?
is correct and often preferred to:
    I can bring red, white or rosé.  Which is better?
but most people would be happy in all but the most formal speech to accept any of these sentences.

However, this all misses the point:
The comparative is exclusive and refers to separate items but the superlative is inclusive and refers to items within the same group.  So for example:
    This wine is better than the others
refers to the fact that I am separating the wine into two groups and the one I want is not part of the group.  However,
    This wine is the best of them all
refers to the group as a whole and the wine I want is included in that group.
So, providing only that the items are seen as inclusive, forming a group, the superlative is natural when singling out one item no matter how large the group and
    This is the best of the two I've tried
is perfectly acceptable.
The comparative may be used for more than two items providing that the item referred to is seen as exclusive and not part of the group and
    I bought this wine because it was better than the other 6 I tried
is also perfectly acceptable.

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Related guides
copular verbs for more on what are called linking verbs in some sources
comparison for more on how we compare things in English
intensifying adjectives for more on a special class of adjectives
adverb modifiers for some consideration of how adjectives are amplified or toned down
gradability for more on a key adjectival phenomenon
markedness for more on how adjectives and other language items are marked
participles for more on how these non-finite forms are used
modification for an overview of how modification works
compounding for more on how compounds are made and the concept of headedness
classifiers and partitives for more on how these special types of modifiers are distinguished from adjectives


There is, of course, a test on some of this.



References:
Chalker, S, 1984, Current English Grammar, London: Macmillan
Crystal, D, 1987, The Encyclopaedia of Language, Cambridge: Cambridge University Press