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

betray \betray"\ b-etr=a", v. t. imp.  p. p.
   betrayed -tr=ad"; p. pr.  vb. n. betraying. oe.
   betraien, bitraien; pref. be- + of. tra"ir to betray, f.
   trahir, fr. l. tradere. see traitor.
   1. to deliver into the hands of an enemy by treachery or
      fraud, in violation of trust; to give up treacherously or
      faithlessly; as, an officer betrayed the city.
      1913 webster

            jesus said unto them, the son of man shall be
            betrayed into the hands of men.       --matt. xvii.
                                                  22.
      1913 webster

   2. to prove faithless or treacherous to, as to a trust or one
      who trusts; to be false to; to deceive; as, to betray a
      person or a cause.
      1913 webster

            but when i rise, i shall find my legs betraying me.
                                                  --johnson.
      1913 webster

   3. to violate the confidence of, by disclosing a secret, or
      that which one is bound in honor not to make known.
      1913 webster

            willing to serve or betray any government for hire.
                                                  --macaulay.
      1913 webster

   4. to disclose or discover, as something which prudence would
      conceal; to reveal unintentionally.
      1913 webster

            be swift to hear, but cautious of your tongue, lest
            you betray your ignorance.            --t. watts.
      1913 webster

   5. to mislead; to expose to inconvenience not foreseen to
      lead into error or sin.
      1913 webster

            genius . . . often betrays itself into great errors.
                                                  --t. watts.
      1913 webster

   6. to lead astray, as a maiden; to seduce as under promise
      of marriage and then abandon.
      1913 webster

   7. to show or to indicate; -- said of what is not obvious at
      first, or would otherwise be concealed.
      1913 webster

            all the names in the country betray great antiquity.
                                                  --bryant.
      1913 webster
see also:
betrayed betraying traitor 

[2] : WordNet (r) 2.0

betray
     v 1: reveal unintentionally; "her smile betrayed her true
          feelings" syn: bewray
     2: deliver to an enemy by treachery; "judas sold jesus"; "the
        spy betrayed his country" syn: sell
     3: disappoint, prove undependable to; abandon, forsake; "his
        sense of smell failed him this time"; "his strength
        finally failed him"; "his children failed him in the
        crisis" syn: fail
     4: be sexually unfaithful to one's partner in marriage; "she
        cheats on her husband"; "might her husband be wandering?"
        syn: cheat on, cheat, cuckold, wander
     5: give away information about somebody; "he told on his
        classmate who had cheated on the exam" syn: denounce, tell
        on, give away, rat, grass, shit, shop, snitch,
         stag
     6: cause someone to believe an untruth; "the insurance company
        deceived me when they told me they were covering my house"
        syn: deceive, lead astray ant: undeceive
see also:
bewray sell fail cheat on cheat cuckold 
wander denounce tell on give away rat 
grass shit shop snitch stag 
deceive lead astray undeceive 

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

132 moby thesaurus words for "betray":
   abuse, apostatize, babble, bamboozle, be indiscreet, be unguarded,
   bear witness against, beguile, betoken, betray a confidence, blab,
   blabber, blow the whistle, bluff, blurt, blurt out, bolt,
   break away, break faith, cajole, cheat on, circumvent, collaborate,
   conjure, cross, debauch, deceive, defect, defile, deflower, delude,
   demonstrate, desert, despoil, diddle, disclose, discover, divulge,
   double-cross, dupe, ensnare, entrap, evidence, evince, expose,
   fail, fink, fool, force, forestall, gammon, get around, give away,
   gull, hoax, hocus-pocus, hoodwink, hornswaggle, humbug, impart,
   indicate, inform, inform against, inform on, juggle, lay bare,
   lead astray, leak, let down, let drop, let fall, let slip,
   manifest, misguide, mislead, mock, narc, outmaneuver, outreach,
   outsmart, outwit, overreach, peach, pigeon, play one false,
   pull out, put something over, rape, rat, ravage, ravish, renegade,
   reveal, reveal a secret, ruin, run out on, secede, seduce, sell,
   sell out, shop, show, sing, snare, snitch, snitch on, snow, soil,
   spill, spill the beans, split, squeal, stool, string along, sully,
   take in, talk, tattle, tattle on, tell, tell on, tell secrets,
   tell tales, testify against, trap, trick, turn in, turn informer,
   two-time, uncover, unveil, violate

Betray >> B Words
Betray, definition of term: Betray
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