An adjective phrase is a group of words that describes a noun or pronoun, providing more detail about it. This phrase typically includes an adjective and may also contain modifiers, such as adverbs or prepositional phrases. For example, in the phrase "very tall building," "very tall" is the adjective phrase that describes the noun building. Adjective phrases can appear before or after the noun they modify. For instance, in the sentence "The cat with fluffy fur is sleeping," the phrase "with fluffy fur" describes the cat. These phrases enhance writing by adding depth and specificity to descriptions.