The Collaborative International Dictionary of English v.0.48:

Vulgarity \Vul*gar"i*ty\, n. [Cf. F. vulgarit['e], L. vulgaritas
   the multitude.]
   [1913 Webster]
   1. The quality or state of being vulgar; mean condition of
      life; the state of the lower classes of society. --Sir T.
      Browne.
      [1913 Webster]

   2. Grossness or clownishness of manners of language; absence
      of refinement; coarseness.
      [1913 Webster]

            The reprobate vulgarity of the frequenters of
            Bartholomew Fair.                     --B. Jonson.
      [1913 Webster]

WordNet (r) 3.0 (2006):

vulgarity
    n 1: the quality of lacking taste and refinement [syn:
         coarseness, commonness, grossness, vulgarity,
         vulgarism, raunch]

Moby Thesaurus II by Grady Ward, 1.0:

106 Moby Thesaurus words for "vulgarity":
   Gothicism, bad manners, bad taste, barbarism, barbarousness,
   baseness, bombasticness, cacology, cacophony, caddishness,
   clumsiness, coarseness, crudeness, cumbrousness, deficiency,
   discourteousness, discourtesy, dysphemism, earthiness, failure,
   fewness, filthiness, foulness, frankness, gaucherie, gracelessness,
   gross behavior, grossness, harshness, heaviness, humbleness,
   ignobility, ill breeding, ill manners, ill-balanced sentences,
   imperfection, impoliteness, impropriety, impurity, inadequacy,
   incivility, incompetence, inconcinnity, inconsiderateness,
   incorrectness, indecorousness, indelicacy, inelegance, inelegancy,
   infelicity, insensitivity, insufficiency, inurbanity,
   lack of finish, lack of polish, lack of refinement, leadenness,
   lewdness, littleness, loutishness, maladroitness, mannerlessness,
   meanness, mediocrity, obscenity, offensiveness, pettiness,
   pompousness, ponderousness, poor diction, raciness, rankness,
   rawness, roughness, rudeness, saltiness, sesquipedalianism,
   sesquipedality, shabbiness, slipshod construction, smallness,
   spiciness, stiltedness, subnormality, tactlessness, tastelessness,
   tawdriness, triviality, turgidity, uncourtliness, uncouthness,
   uneuphoniousness, ungallantness, ungentlemanliness, ungracefulness,
   ungraciousness, unmannerliness, unpoliteness, unrefinement,
   unseemliness, unskillfulness, unsolicitousness, unsophistication,
   unwieldiness, vileness, vulgarism