not true to duty or obligation or promises; an unfaithful lover'

having sexual relations with someone other than your husband or wife, or your boyfriend or girlfriend; her husband was unfaithful'

having the character of, or characteristic of, a traitor; the faithless Benedict Arnold; a lying traitorous insurrectionist

[ Syn: faithless , traitorous , treasonable , treasonous ]

not trustworthy; an unfaithful reproduction'