An adjective is a word that tells us more about a noun. It "describes" or "modifies" a noun.

A. An adjective often comes BEFORE a noun: for example -
1. A green car
2. A blue sky
3. An interesting story

B. And sometimes an adjective comes AFTER a verb: for example -
1. My car is blue.
2. The sky became dark.
3. His story seemed interesting.

C. Adjectives can also modify pronouns : for example -
1. They were empty.
2. It seemed to be strange.
3. Those gifts are not expensive.