treacherous
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/icons/point.icon FAITHLESS, FALSE, DISLOYAL, TRAITOROUS, TREACHEROUS, PERFIDIOUS mean untrue to what should command one's fidelity or allegiance.
FAITHLESS applies to any failure to keep a promise or pledge or any breach of allegiance or loyalty.
e.g. faithless allies
FALSE stresses the fact of failing to be true in any manner ranging from fickleness to cold treachery.
e.g. betrayed by false friends
DISLOYAL implies a lack of complete faithfulness to a friend, cause, leader, or country.
e.g. disloyal to their country
TRAITOROUS implies either actual treason or a serious betrayal of trust.
e.g. traitorous acts punishable by death
TREACHEROUS implies readiness to betray trust or confidence.
e.g. a treacherous adviser
PERFIDIOUS adds to
FAITHLESS the implication of an incapacity for fidelity or reliability.
e.g. a perfidious double-crosser
adjective
guilty of or involving betrayal or deception:
〈人･言動などが〉不誠実な, 裏切りの
e.g. a treacherous Gestapo agent
e.g. memory is particularly treacherous.
(of ground, water, conditions, etc.) hazardous because of presenting hidden or unpredictable dangers:
〈天候･記憶などが〉当てにならない; 〈道路などが〉(安全に見えて)危険な, 油断できない
e.g. a vacationer was swept away by treacherous currents.
DERIVATIVES
treacherously |ˈtreCH(ə)rəslē| adverb
treacherousness |ˈtreCH(ə)rəsnəs| noun
ORIGIN
Middle English (in treacherous (sense 1 of the adjective)): from Old French trecherous, from trecheor ‘a cheat’, from trechier ‘to cheat’.