Word family noun faith faithfulness ≠ unfaithfulness faithful faithlessness adjective faithful ≠ unfaithful faithless adverb faithfully ≠ unfaithfully
From Longman Dictionary of Contemporary Englishfaithlessfaith‧less /ˈfeɪθləs/ adjective formal FAITHFULsomeone who is faithless cannot be trusted SYN untrustworthy a faithless friend —faithlessness noun [uncountable]Examples from the Corpus
faithless• Were all men faithless, driven only by their own needs?• The despairing, faithless, gaping, horrified wife looked down at her lover, and knew that he was dead.• a faithless husband• Moses is caught between two fires as it were: a faithless people and a vengeful Lord.• Not to mention the fact that he has been conspicuously faithless to me.