The Collaborative International Dictionary of English v.0.48:

Grandiloquence \Gran*dil"o*quence\, n.
   The use of lofty words or phrases; bombast; -- usually in a
   bad sense.
   [1913 Webster]

         The sin of grandiloquence or tall talking. --Thackeray,
   [1913 Webster]

WordNet (r) 3.0 (2006):

grandiloquence
    n 1: high-flown style; excessive use of verbal ornamentation;
         "the grandiosity of his prose"; "an excessive ornateness of
         language" [syn: grandiosity, magniloquence,
         ornateness, grandiloquence, rhetoric]

Moby Thesaurus II by Grady Ward, 1.0:

80 Moby Thesaurus words for "grandiloquence":
   affectation, aggrandizement, amplification, ballyhoo, big talk,
   blowing up, burlesque, caricature, command of language, dilatation,
   dilation, enhancement, enlargement, exaggerating, exaggeration,
   excess, exorbitance, expansion, expression of ideas, extravagance,
   extreme, fashion, feeling for words, form of speech,
   grace of expression, hard word, heightening, huckstering,
   hyperbole, hyperbolism, inflation, inordinacy, jawbreaker,
   lexiphanicism, literary style, long word, magnification, manner,
   manner of speaking, mannerism, mode, mode of expression,
   orotundity, overemphasis, overestimation, overkill, overstatement,
   peculiarity, personal style, polysyllable, pomposity, pompousness,
   pontificality, pontification, prodigality, profuseness, puffery,
   puffing up, rhetoric, self-importance, sensationalism,
   sense of language, sesquipedalian, strain, stretching, stuffiness,
   style, stylistic analysis, stylistics, superlative, tall talk,
   the grand style, the plain style, the sublime, touting, travesty,
   trick, turgidity, vein, way