The Collaborative International Dictionary of English v.0.48:

Flatulent \Flat"u*lent\, a. [L. flatus a blowing, flatus ventris
   windiness, flatulence, fr. flare to blow: cf. F. flatulent.
   See Blow.]
   1. Affected with flatus[2] or gases generated in the
      alimentary canal; windy.
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   2. Generating, or tending to generate, wind in the stomach.
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            Vegetables abound more with a["e]rial particles than
            animal substances, and therefore are more flatulent.
                                                  --Arbuthnot.
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   3. Turgid with flatus; as, a flatulent tumor. --Quincy.
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   4. Pretentious without substance or reality; puffy; empty;
      vain; as, a flatulent vanity.
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            He is too flatulent sometimes, and sometimes too
            dry.                                  --Dryden.
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WordNet (r) 3.0 (2006):

flatulent
    adj 1: generating excessive gas in the alimentary canal
    2: suffering from excessive gas in the alimentary canal [syn:
       colicky, flatulent, gassy]

Moby Thesaurus II by Grady Ward, 1.0:

47 Moby Thesaurus words for "flatulent":
   bloated, blown up, bombastic, dilated, distended, dropsical,
   edematous, ejaculative, ejective, empty, enchymatous, eructative,
   expulsive, extrusive, fat, formal, fustian, gassy, grandiloquent,
   hollow, incrassate, inflated, mouthy, overblown, plethoric,
   pompous, pontifical, puffed up, puffy, pursy, self-important,
   shallow, solemn, stilted, stuffy, superficial, swelled, swollen,
   tumescent, tumid, turgescent, turgid, vain, ventose, vomitive,
   vomitory, windy