themselves

Themselves is a reflexive and intensive pronoun used with the third-person plural subject they. As a reflexive pronoun, it refers back to a plural antecedent and functions as the object of a verb or a preposition. For example: They prepared themselves for the trip, or The students saw themselves in the mirror. The pronoun agrees in number with the subject, not with the object.

Themselves can also serve as an intensive (emphatic) pronoun. In intensive use, it emphasizes the subject rather than referring back to it. For instance: The team themselves won the championship, or The protesters themselves spoke to the crowd. In these cases, the pronoun is not strictly necessary for grammatical function but serves to stress the subject.

Singular use is a matter of style and convention. With singular they, some writers and style guides use themselves as the reflexive pronoun, as in: Someone left their bag; they should take care of themselves. Others prefer the gender-specific forms himself or herself, or advocate the variant themself for a singular antecedent. The word themself exists in some theorizations as an alternative but remains less widely accepted in formal contexts.

In summary, themselves is the standard reflexive and intensive pronoun for plural they, with growing use in singular they contexts in some varieties of English. It helps express reflexive action, emphasis, and agreement across person and number in contemporary usage.