In grammar, a moifier (or qualifier) is a word or sentence element that limits or qualifies another word, a phrase, or a clause. In English, there are two kinds of modifiers: adjectives, which modify nouns and pronouns, and adverbs, which modify verbs, adjectives, and other adverbs. A modifier phrase is a phrase that acts as a modifier; English has adjective phrases and adverb phrases. Neither modifiers nor modifier phrases are usually required by a clause's syntax; they are optional, and help clarify or limit the extent of the meaning of the word or phrase they modify.