Syntagmatic realizations of the subject. phrase in the part called Syntax of Grammar, the subject is in a sentence, that which is not part of the predicate and is constitutes its support. The subject is, then, that (person, animal or thing) of which the same is said. The subject is, then, that (person, animal or thing) of which it is said or comments on something in a sentence and that agrees on a morpheme of number and morpheme of person with the verb that is the nucleus of the predicate