Added 10 October 2026 treasonous adjective Categories: Describing WordsRare Words adjective ! Definition from Wiktionary (CC BY-SA). More about treasonous at Wordnik → Where our words come from → Like or in the way of treason. His treasonous actions earned Benedict Arnold eternal scorn. Related Words: traitoroustreasonabledisloyaltreasonfultraitorlytreacheroustreachersomedastardlytheftuousjudaslikescoundrelousfalse-hearted Back to today's word