n. One who defends; one who protects from injury; a champion.n. One who maintains, supports, or vindicates by force or argument.n. In Scots law, the defendant; the party against whom the conclusions of a process or action are directed.n. In Irish history, one of an association of Roman Catholics organized in the north of Ireland in the eighteenth century to oppose the Protestants who had organized as Peep-o'-day Boys or Orangemen.