To give authority, warrant, or legal power to; empower (a person): as, to authorize commissioners to settle the boundary of a state.To give authority for; approve of and permit; formally sanction (an act or a proceeding).To make authoritative or valid; legalize; validate.To establish by authority or usage: as, an authorized idiom.To warrant; vouch for.To support (one's self) upon the authority (of).Also spelled authorise.