[1] : The Collaborative International Dictionary of English v.0.48

unfaithful \unfaith"ful\, a.
   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.
      1913 webster

            my feet, through wine, unfaithful to their weight.
                                                  --pope.
      1913 webster

            his honor rooted in dishonor stood,
            and faith unfaithful kept him falsely true.
                                                  --tennyson.
      1913 webster

   2. not possessing faith; infidel. r. --milton.
      1913 webster -- unfaith"fully, adv. --
      unfaith"fulness, n.
      1913 webster
see also:
unfaith"fully unfaith"fulness 

[2] : WordNet (r) 2.0

unfaithful
     adj 1: not true to duty or obligation or promises; "an unfaithful
            lover" ant: faithful
     2: having sexual relations with someone other than your husband
        or wife, or your boyfriend or girlfriend; "her husband was
        unfaithful" ant: faithful
     3: deliberately and abominably disloyal or likely to betray
        trust or confidence; "the faithless benedict arnold"; "a
        lying traitorous insurrectionist" syn: faithless, traitorous
     4: not trustworthy; "an unfaithful reproduction"
see also:
faithful faithless traitorous 

[3] : Moby Thesaurus II by Grady Ward, 1.0

28 moby thesaurus words for "unfaithful":
   derelict, disaffected, disloyal, disregardful, faithless, false,
   fickle, inattentive, inconstant, inobservant, negligent,
   nonadherent, noncompliant, nonconforming, nonobservant,
   not true to, of bad faith, perfidious, recreant, traitorous,
   treacherous, trothless, uncompliant, unconforming, unloyal,
   unobservant, unsteadfast, untrue

Unfaithful >> U Words
Unfaithful, definition of term: Unfaithful
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