Faithless

прилагательное 1) вероломный, изменнический, предательский Синоним(ы): treacherous, unfaithful, perfidious, disloyal 2) нетвёрдый, неустойчивый, ненадёжный; обманчивый, иллюзорный, вводящий в заблуждение Синоним(ы): unstable, treacherous, shifting, delusive 3) неверующий; неверный

Большой англо-русский словарь

Faithless

adjective 1. not true to allegiance or duty; treacherous, disloyal Example: a faithless servant 2. not to be relied on; untrustworthy Example: a faithless toolfaithlessly adverbfaithlessness noun Synonyms: 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 Example: faithless allies. false stresses the fact of failing to be true in any manner ranging from fickleness to cold treachery Example: betrayed by false friends. disloyal implies a lack of complete faithfulness to a friend, cause, leader, or country Example: disloyal to their country. traitorous implies either actual treason or a serious betrayal of trust Example: traitorous acts punishable by death. treacherous implies readiness to betray trust or confidence Example: a treacherous adviser. perfidious adds to faithless the implication of an incapacity for fidelity or reliability Example: a perfidious double-crosser.

Merriam-Webster's Collegiate Dictionary