1. Not faithful; not observant of promises, vows, allegiance, or duty; violating trust or confidence; treacherous; perfidious; as, an unfaithful subject; an unfaithful agent or servant.
My feet, through wine, unfaithful to their weight. --Pope.
His honor rooted in dishonor stood,
And faith unfaithful kept him falsely true. --Tennyson.
2. Not possessing faith; infidel. [R.]
-- Un*faith*ful*ly, adv. -- Un*faith*ful*ness, n.
n : the quality of being unfaithful [syn: infidelity] [ant: fidelity,