The Collaborative International Dictionary of English v.0.48:

Verbosity \Ver*bos"i*ty\, n.; pl. Verbosities. [L. verbositas:
   cf. F. verbosit['e].]
   The quality or state of being verbose; the use of more words
   than are necessary; prolixity; wordiness; verbiage.
   [1913 Webster]

         The worst fault, by far, is the extreme diffuseness and
         verbosity of his style.                  --Jeffrey.
   [1913 Webster]

WordNet (r) 3.0 (2006):

verbosity
    n 1: an expressive style that uses excessive or empty words
         [syn: verboseness, verbosity] [ant: terseness]

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "verbosity":
   bedizenment, big mouth, bombast, candor, cloud of words,
   communicativeness, conversableness, duplication,
   duplication of effort, effusion, effusiveness, embellishment,
   expletive, extravagance, fat, featherbedding, filling,
   flow of words, flowing tongue, fluency, fluent tongue,
   flux de bouche, flux de paroles, flux of words, frankness, frill,
   frills, frippery, garrulity, garrulousness, gassiness, gift of gab,
   gingerbread, glibness, grandiloquence, gregariousness, gush,
   gushiness, logorrhea, long-windedness, longiloquence, loose tongue,
   loquaciousness, loquacity, luxury, needlessness, openness,
   ornamentation, overadornment, overlap, padding, payroll padding,
   pleonasm, prolixity, redundance, redundancy, slush, sociability,
   spate of words, superfluity, superfluousness, talkativeness,
   tautology, unnecessariness, verbalism, verbality, verbiage,
   verboseness, volubility, windiness, wordiness