1. (n.) The disciple who betrayed Christ. Hence: A treacherous person; one who betrays under the semblance of friendship.

2. (a.) Treacherous; betraying.

Benedict Arnold Brutus Judas Iscariot Quisling archtraitor betrayer cockatrice conniver conspirator conspirer convict criminal crook deceiver desperado desperate criminal double agent double-crosser double-dealer felon fugitive gallows bird gangster gaolbird informer intrigant intriguer jailbird lawbreaker machinator mobster outlaw plotter public enemy quisling racketeer rat schemer scofflaw serpent snake swindler thief thug timeserver traitor treasonist trimmer turncoat two-timer