Adjectives modify (limit the meaning of) nouns and pronouns, usually by describing, identifying, or quantifying those words. Adjectives that identify or quantify are sometimes called determiners.
The red Corvette ran off the road. [describes]
That Corvette needs to be repaired. [identifies]
We saw several other Corvettes race by. [quantifies]
In addition to their basic forms, most descriptive adjectives have other forms that allow you to make comparisons: small, smaller, smallest; foolish, more foolish, most foolish, less foolish, least foolish.
This year’s attendance was smaller than last year’s.
Adjectives usually precede the words they modify, though they may follow linking verbs: The car was defective. Many pronouns can function as identifying adjectives when they are followed by a noun.
That is a dangerous intersection. [pronoun]
That intersection is dangerous. [identifying adjective]
Other kinds of adjectives that identify or quantify are the articles a, an, and the and numbers (three, sixty-fifth, five hundred).
Proper adjectives, which are capitalized form from or relate to proper nouns (Egyptian, Emersonian).