ˈtrād.ərəs, -ātər-, -ā.tr- adjective
Etymology: Middle English traytrous, from Middle French traitreux, from Old French, from traitre traitor + -eux -ous — more at traitor
: having the nature or quality of a traitor or of treason or betrayal : false , perfidious , treacherous , treasonable
Synonyms: see faithless