perfidiousness

lack of faithfulness especially to one's husband or wife perfidiousness seems to descend to a whole other level when a husband cheats on a wife who's terminally ill Synonyms disloyalty, faithlessness, falseness, falsity, inconstancy, infidelity, perfidy, unfaithfulnessRelated Words adultery; betrayal, double-cross, double-dealing, duplicity, sellout, treachery, treason; deceit, deception, lyingNear Antonyms staunchness, steadfastness; dependability, reliability; honesty, trustworthinessAntonyms allegiance, constancy, devotedness, devotion, faith, faithfulness, fealty, fidelity, loyalty