one who pleads the cause of another. specifically: one who pleads the cause of another before a tribunal or judicial court; a counselor.-one who defends, vindicates, or espouses any cause by argument; a pleader; as, an advocate of free trade, an advocate of truth.-christ, considered as an intercessor.-to plead in favor of; to defend by argument, before a tribunal or the public; to support, vindicate, or recommend publicly.-to act as advocate.