| Adj. | 1. | unfaithful - not true to duty or obligation or promises; "an unfaithful lover"inconstant - likely to change frequently often without apparent or cogent reason; variable; "inconstant affections"; "an inconstant lover"; "swear not by...the inconstant moon"- Shakespeare faithful - steadfast in affection or allegiance; "years of faithful service"; "faithful employees"; "we do not doubt that England has a faithful patriot in the Lord Chancellor" | |
| 2. | unfaithful - having sexual relations with someone other than your husband or wife, or your boyfriend or girlfriend; "her husband was unfaithful"faithful - not having sexual relations with anyone except your husband or wife, or your boyfriend or girlfriend; "he remained faithful to his wife" | |
| 3. | unfaithful - deliberately and abominably disloyal or likely to betray trust or confidence; "the faithless Benedict Arnold"; "a lying traitorous insurrectionist"disloyal - deserting your allegiance or duty to leader or cause or principle; "disloyal aides revealed his indiscretions to the papers" | |
| 4. | unfaithful - not trustworthy; "an unfaithful reproduction"inaccurate - not accurate; "an inaccurate translation"; "the thermometer is inaccurate" | |