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.
- Not adhering to promises, obligations, or allegiances; disloyal. See Synonyms at faithless.
- Not true or constant to one's sexual partner.
- Not true to one's spouse; guilty of adultery.
- Not justly representing or reflecting the original; inaccurate.
- Obsolete Deficient in or lacking religious faith; unbelieving.