1. Syntactic Functions of Adjectives
INTRODUCTION TO ENGLISH PHRASES

2. (1) ATTRIBUTIVE (Pre-modifying nouns)
The beautiful painting.
His main argument.
My former friend.
These are all examples of noun phrases that include an adjective phrase. In these cases, the adjective phrases are only the adjectives themselves, for the words that come in front of them are not adverbs.

3. (2) PREDICATIVE
They come after a linking verb “be”, “become”, etc, in the predicative function: complement of the subject or of the object.
E.g.:
[I] feel awful. (complement of the subject)
I consider [him] foolish. (complement of the object)
[That he needs it] is obvious. (complement of the subject, in this case, a subject clause)

4. (3) POST-MODIFIER
E.g.:
The people (who were) involved were reported to the police.
(Post-modifier: Reduced wh- clause)
The men (who were) present were his supporters.
Anyone intelligent can do it.
I want to try something larger.
(Adjectives after indefinite pronouns)

5. (4) HEAD OF A NOUN PHRASE
Adjectives as nouns of a noun phrase have personal references (Often adjectives denoting nationalities or with abstract references).
The extremely old need a great deal of attention.
The young in spirit enjoy life.
He’s acceptable to both old and young.
You British and you French ought to be allies.

6. (5) VERBLESS ADJECTIVE CLAUSE
It generally refers to the subject. An adjective (alone or as head of an adjective phrase) can function as a verbless clause.
E.g.:
Nervous, the man opened the letter.
The man, (who was) nervous, opened the letter.

7. (6) EXCLAMATORY ADJECTIVE SENTENCE
An adjective as head of an adjective phrase or as its sole realization can be exclamation.
E.g.:
How good of you!
How wonderful!
Excellent!