Emily Dickinson Lexicon

UN-FAITH'FUL, a.

1. 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.
2. Not performing the proper duty. My feet through wine unfaithful to their weight. Pope.
3. Impious; infidel. Milton.
4. Negligent of duty; as, an unfaithful workman.