What are the subject and predicate of a sentence? Subject and predicate are two vocabulary words we can use to talk about sentences. Younger students do not need to know this vocabulary, but older students may find it helpful as they are learning about different ways to compose a sentence. The subject of a sentence is the noun or pronoun doing the action, as well as any supporting words such as articles or adjectives. The predicate of a sentence is the verb or action of the sentence and any supp