infidelity

1 lack of faithfulness especially to one's husband or wife infidelity can lead to divorce Synonyms disloyalty, faithlessness, falseness, falsity, inconstancy, perfidiousness, perfidy, unfaithfulness Related Words adultery; betrayal, double-cross, double-dealing, duplicity, sellout, treachery, treason; deceit, deception, lying Near Antonyms staunchness, steadfastness; dependability, reliability; honesty, trustworthiness Antonyms allegiance, constancy, devotedness, devotion, faith, faithfulness, fealty, fidelity, loyalty

2 the act or fact of violating the trust or confidence of another the one thing that the political boss will not forgive is infidelity Synonyms backstabbing, business, disloyalty, double cross, faithlessness, falseness, falsity, betrayal, perfidy, sellout, treachery, treason, two-timing, unfaithfulnessRelated Words abandonment, desertion; deceit, deception, double-dealing, duplicity, guile, two-facedness; fraud, informing, lying, snitching, talebearing, trickeryNear Antonyms dependability, reliability, trustworthiness; defense, protection, safeguard, shieldAntonyms allegiance, devotion, faithfulness, fealty, fidelity, loyalty, staunchness, steadfastness

3 a sexual encounter or relationship between a married person and someone other than their spouse had known about his wife's infidelities for years Synonyms cheating, adultery, misconduct, two-timing, unfaithfulnessRelated Words criminal conversation; free love, promiscuity; disloyalty, faithlessness, falseness, inconstancy, perfidiousness, perfidy, treachery; affair (also affaire), amour, fling, love, love affair, romance; intrigue; attachment, infatuation; entanglement, flirtation; liaison, passionNear Antonyms allegiance, constancy, dedication, devotedness, devotion, fealty, loyalty, steadfastnessAntonyms faithfulness, fidelity