Un-fāith'ful, a.

a. 1. Not faithful; not observant of promises, vows, allegiance, or duty; violating trust or confidence; treacherous; perfidious; as, an unfaithful subject; an unfaithful husband or wife; an unfaithful servant; an unfaithful bailee or agent. My feet through wine unfaithful to their weight. Pope. 2. Not possessing faith; infidel. [Rare.] Milton.