Simple:
* An adjective is a word that describes a noun.
More specific:
* An adjective is a word that modifies a noun or pronoun, providing more information about its qualities, characteristics, or states.
Technical:
* An adjective is a word class that typically functions as a modifier in a phrase, modifying a noun or pronoun by providing more information about its qualities, characteristics, or states. Adjectives can be attributive (placed directly before the noun) or predicative (linked to the noun by a linking verb).
Examples:
* The *big* red *truck* is parked outside. (big and red are adjectives modifying the noun "truck")
* The children are *happy*. (happy is an adjective linked to the noun "children" by the linking verb "are")
Key takeaway: Adjectives are words that add detail and meaning to nouns and pronouns. They help us paint a more vivid picture with language.