The adjective "cock-a-hoop" comes from a curious 16th- and 17th-century expression, "to set cock a hoop," which meant "to be festive" or "to drink or celebrate without restraint." Etymologists, however, are not entirely certain about the origin of that old expression. Although no one knows if it originally had any connection with the "rooster" sense of "cock," many people thought it did — and this perceived association influenced the current meaning of "cock-a-hoop." The cock is known for its triumphant crow, and "cock-a-hoop" is now used to refer to something triumphantly boastful.