Oneself vs. Themself — What's the Difference?

A person's self: general form of himself, herself, themself or yourself.

Used instead of ‘himself’ or ‘herself’ to refer to a person of unspecified sex

A reflexive form of the indefinite pronoun one. Commonly written as two words, one's self.

(reflexive pronoun) The reflexive form of they, the third-person singular personal pronoun. The single person previously mentioned, as the object of a verb or following a preposition also used for emphasis.

Synonym of themselves.