INFIDELITY

n. 1 unfaithfulness, faithlessness, treachery, traitorousness, disloyalty, perfidy, falseness, apostasy, heresy The infidelity of his supporters brought about his downfall 2 adultery, cuckoldry; affair, liaison, amour, Colloq cheating Infidelity is a common cause of marriage break-up She forgave him his many infidelities.