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Concourse 2

Adjectives

adjectives


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

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 being tall.
  2. Stative adjectives are not used with imperatives: we cannot have *Be tall, *Don't be French, *Be thin, *Be important for example.

Dynamic adjectives, by contrast, are to some extent under the control of whoever or whatever they describe.
Examples are: agreeable, obedient, proud, calm, careful, cruel, difficult, 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 being 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 being troublesome is another pathetic fallacy.

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 being 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 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
    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
    and
        Don't be suspicious!
    but not
        *Be suspicious!
    or
        *They are being suspicious.
  2. Some of these, mostly the negative ones, only allow a negative imperative: jealous, obnoxious etc.  We 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.)

eggs

Predicative or Attributive?

An attributive adjective pre-modifies the noun it describes.
For example:
    the lovely picture
    the huge population
    the deafening roar
etc.
A predicative adjective follows the noun (after a copular 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).

Note that 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.)
Predicative adjectives 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
    and
        The customers were patient
    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.

in front of

Adjectives only used attributively (before the noun)

  1. Intensifiers and limiters
    Intensifiers enhance meaning and limiters restrict it.  The most common 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 uses
    In non-intensifying and non-limiting meanings, some can be used predicatively.  Compare, for example:
        His work was complete (non-intensifying)
    with
        He is a complete fool (intensifying)
    and
        the measurement was precise (non-limiting)
    with
        the precise reason (limiting))

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

    See the guide to intensifying adjectives for more.

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.

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 + verb (-ing or -ed)
    heart-stopping
    handmade
    car producing
    machine cut
  2. adverbial + verb
    seagoing
    self-starting
    easy listening
    brain friendly
  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 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 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 richer

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:
tall,
not short, good not bad, permanent not impermanent, large not small, 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.).

    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 below).


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 equally 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
all of which appear to be 'wrong' but are 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.


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 can only be used attributively so we have the civil law (not the law is civil) and 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
        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 tiled roof
    and
        the roof is tiled
    but not
        *the tiledest roof
    or
        *the roof is less tiled

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 (note the postpositive use) 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
    the young
    the meek
    the foolish
    the wise
    the unmarried
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.

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 rude customer

English allows adjectives to act as nouns (with the definite article usually) as we saw above and also in expressions such as
    the filthy rich
    the very wise
    the extremely ill
    the perfidious English
etc. (with and without modification).
Note, too, uses such as
    from the sublime to the ridiculous
.
These can only be attributive in terms of word order because any attempt to use them predicatively results in, e.g.
    the rich are filthy
which is unlikely to be true and not at all what is meant.


ordering

Attributive adjective position

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 postpositive 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
  5. A few adjectives conventionally follow the noun but can vary in meaning depending on whether they precede or follow it:
        The people involved in the accident
    refers to fact that the people were in the accident, but there is a distinction between
        The police officer concerned took statements from everyone
    which refers to the police officer who was dealing with the accident, and
        The concerned police officer took statements from everyone
    which refers to the fact that the police officer was worried in some way.
    Equally,
        the students present
    refers only to the student who are here, but
        the present students
    refers to everyone who is currently a student.
    It may be helpful to consider 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. 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

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
    is 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 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 below).


classify

Epithets and classifiers

When nouns are used adjectivally, they are normally classifiers.  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.

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.


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
    *The money is 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 Old English forms which survive as adjectives only and they include: drunken, sunken, shrunken, learned, blessed, beloved.
(In the last three cases, the adjective retains the earlier syllabic pronunciation of -ed as /lɜːnɪd/, /blesɪd/ and /bɪ.ˈlʌ.vɪd/ rather than /lɜːnd/, /blest/ and /bɪ.ˈlʌvd/ which are how the past participles of the verbs are pronounced.)
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.

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 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.

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.

As far as it goes the twin rule works but it soon breaks down, unfortunately, and getting learners to rely on it 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.
  • NNo 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.



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 this.



Reference:
Crystal, D, 1987, The Encyclopaedia of Language, Cambridge: Cambridge University Press