adj. 1. a. Not adhering to promises, obligations, or allegiances; disloyal. See Synonyms at faithless. b. Breaking trust in a marriage or relationship by having sexual relations with someone other than one's spouse or sexual partner. 2. Not justly representing or reflecting the facts or a primary source; inaccurate: an account that was unfaithful to what really happened; a translation that was unfaithful to the original. un·faithful·ly adv. un·faithful·ness n. |
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