Webster's Revised Unabridged Dictionary · 1913

Traitorous

Traitorous , adjective

[Compare French traîtreux.]

1.
Guilty of treason; treacherous; perfidious; faithless; as, a traitorous officer or subject. — Shakespeare
2.
Consisting in treason; partaking of treason; implying breach of allegiance; as, a traitorous scheme.