Source : Webster's Revised Unabridged Dictionary (1913)

Traitorous \Trai"tor*ous\, a. [Cf. F. tra[^i]treux.]
   1. Guilty of treason; treacherous; perfidious; faithless; as,
      a traitorous officer or subject. --Shak.

   2. Consisting in treason; partaking of treason; implying
      breach of allegiance; as, a traitorous scheme. --
      {Trai"tor*ous*ly}, adv. -- {Trai"tor*ous*ness}, n.

Source : WordNet®

traitorous
     adj 1: deliberately and abominably disloyal or likely to betray
            trust or confidence; "the faithless Benedict Arnold";
            "a lying traitorous insurrectionist" [syn: {faithless},
             {unfaithful}]
     2: constituting treason; "a traitorous act"; "treasonable acts
        like sabotage" [syn: {treasonable}, {treasonous}]