(NOT LOYAL) [adjective] [esp. old use] - (of a person) guilty of deceiving and lacking loyaltyVargas plays the part of treacherous aristocrat who betrays his king and country.I get a nagging sense of being treacherous to my own sex if I ever make general criticisms of women.
TREACHEROUS
Meaning of TREACHEROUS in English
Cambridge English vocab. Кембриджский английский словарь. 2012