An adjective is a describing word used to modify nouns. Adjectives usually come before the noun and can also follow linking verbs. There are three types of adjectives: regular adjectives that compare two things using "er" and superlatives using "est"; adjectives ending in consonant-vowel-consonant that double the last letter before adding "er" or "est"; and adjectives ending in "y" that drop the "y" before adding "ier" or "iest". Some adjectives are irregular like "good" and "bad". Adjectives are used to compare size, speed, or rank things as most or least of a quality.