The Collaborative International Dictionary of English v.0.48:

Brag \Brag\, v. t.
   To boast of. [Obs.] --Shak.
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The Collaborative International Dictionary of English v.0.48:

Brag \Brag\, n.
   1. A boast or boasting; bragging; ostentatious pretense or
      self glorification.
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            C[ae]sar . . . made not here his brag
            Of "came," and "saw," and "overcame." --Shak.
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   2. The thing which is boasted of.
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            Beauty is Nature's brag.              --Milton.
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   3. A game at cards similar to bluff. --Chesterfield.
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The Collaborative International Dictionary of English v.0.48:

Brag \Brag\, a. [See Brag, v. i.]
   Brisk; full of spirits; boasting; pretentious; conceited.
   [Archaic]
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         A brag young fellow.                     --B. Jonson.
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The Collaborative International Dictionary of English v.0.48:

Brag \Brag\, adv.
   Proudly; boastfully. [Obs.] --Fuller.
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The Collaborative International Dictionary of English v.0.48:

Brag \Brag\, v. i. [imp. & p. p. Bragged; p. pr. & vb. n.
   Bragging.] [OE. braggen to resound, blow, boast (cf. F.
   braguer to lead a merry life, flaunt, boast, OF. brague
   merriment), from Icel. braka to creak, brak noise, fr. the
   same root as E. break; properly then, to make a noise, boast.
   ?95.]
   To talk about one's self, or things pertaining to one's self,
   in a manner intended to excite admiration, envy, or wonder;
   to talk boastfully; to boast; -- often followed by of; as, to
   brag of one's exploits, courage, or money, or of the great
   things one intends to do.
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         Conceit, more rich in matter than in words,
         Brags of his substance, not of ornament. --Shak.
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   Syn: To swagger; boast; vapor; bluster; vaunt; flourish; talk
        big.
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WordNet (r) 3.0 (2006):

brag
    adj 1: exceptionally good; "a boss hand at carpentry"; "his brag
           cornfield" [syn: boss, brag]
    n 1: an instance of boastful talk; "his brag is worse than his
         fight"; "whenever he won we were exposed to his gasconade"
         [syn: brag, bragging, crow, crowing, vaporing,
         line-shooting, gasconade]
    v 1: show off [syn: boast, tout, swash, shoot a line,
         brag, gas, blow, bluster, vaunt, gasconade]

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "brag":
   Captain Bobadil, Gascon, Texan, big mouth, blow, blower, blowhard,
   bluff, bluster, bluster and bluff, blusterer, boast, boaster,
   boastfulness, boasting, bombast, bounce, braggadocio, braggart,
   braggartism, bragging, bravado, bully, cock-a-doodle-doo, conceit,
   crow, draw the longbow, fanfaron, fanfaronade, flourish, gasbag,
   gasconade, gasconader, gasconism, hector, heroics, hot-air artist,
   intimidate, jactation, jactitation, miles gloriosus, mouth,
   out-herod Herod, prate, puff, rage, rant, rave, rodomontade,
   roister, rollick, show off, side, slang, speak for Buncombe,
   splutter, sputter, storm, strut, swagger, swashbuckle, talk big,
   trumpet, vanity, vapor, vaunt, vauntery, vaunting, windbag,
   windjammer, windy