The Collaborative International Dictionary of English v.0.48:

Vulgarism \Vul"gar*ism\, n. [Cf. F. vulgarisme.]
   [1913 Webster]
   1. Grossness; rudeness; vulgarity.
      [1913 Webster]

   2. A vulgar phrase or expression.
      [1913 Webster]

            A fastidious taste will find offense in the
            occasional vulgarisms, or what we now call "slang,"
            which not a few of our writers seem to have
            affected.                             --Coleridge.
      [1913 Webster]

WordNet (r) 3.0 (2006):

vulgarism
    n 1: an offensive or indecent word or phrase [syn: obscenity,
         smut, vulgarism, filth, dirty word]
    2: the quality of lacking taste and refinement [syn:
       coarseness, commonness, grossness, vulgarity,
       vulgarism, raunch]

Moby Thesaurus II by Grady Ward, 1.0:

76 Moby Thesaurus words for "vulgarism":
   Babbittry, Gothicism, bad taste, barbarism, barbarousness,
   bombasticness, bourgeois taste, cacology, cacophony, camp,
   campiness, clumsiness, coarseness, colloquialism, corruption,
   crudeness, cumbrousness, dysphemism, gracelessness, grossness,
   harshness, heaviness, high camp, ill-balanced sentences,
   impropriety, impurity, inappropriateness, inconcinnity,
   incorrectness, indecency, indecorousness, indecorum, indelicacy,
   inelegance, inelegancy, infelicity, kitsch, lack of finish,
   lack of polish, leadenness, localism, low camp, philistinism,
   pompousness, ponderousness, poor diction, poor taste, pop,
   pop culture, roughness, rudeness, sesquipedalianism,
   sesquipedality, slang, slipshod construction, solecism,
   stiltedness, taboo word, tastelessness, turgidity, unaestheticism,
   unaestheticness, unbecomingness, uncouthness, uneuphoniousness,
   unfittingness, ungracefulness, unrefinement, unseemliness,
   unsuitability, unsuitableness, unwieldiness, vernacularism,
   vulgar taste, vulgarity, vulgarness