faithless

a.背信弃义的，不忠实的

fair-to-middling, fair-weather friend, fairground, fairly, fairness, fairway, fairy, fairy godmother, fairy lights, fairy story, fairy-tale, fairy tale, fairy-tale, fairyland, fait accompli, faith, faith-cure, faith-healer, faithful, faithfully, faithfulness, faithlessly, faithlessness, fake, faker, fakir, falcon, falconer, falconry, fall, fall apart, fall away, fall back, fall back on, fall behind, fall behind (sb/sth), fall by the wayside, fall down, fall for, fall for sb, fall guy,