The Collaborative International Dictionary of English v.0.48:

Incivility \In`ci*vil"i*ty\, n.; pl. Incivilities. [L.
   incivilitas: cf. F. incivilit['e].]
   [1913 Webster]
   1. The quality or state of being uncivil; lack of courtesy;
      rudeness of manner; impoliteness. --Shak. Tillotson.
      [1913 Webster]

   2. Any act of rudeness or ill breeding.
      [1913 Webster]

            Uncomely jests, loud talking and jeering, which, in
            civil account, are called indecencies and
            incivilities.                         --Jer. Taylor.
      [1913 Webster]

   3. Lack of civilization; a state of rudeness or barbarism.
      [R.] --Sir W. Raleigh.

   Syn: Impoliteness; uncourteousness; unmannerliness;
        disrespect; rudeness; discourtesy.
        [1913 Webster]

WordNet (r) 3.0 (2006):

incivility
    n 1: deliberate discourtesy [ant: civility]

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "incivility":
   Gothicism, Neanderthalism, animality, bad manners, barbarism,
   barbarity, barbarousness, bestiality, boorishness, brutality,
   brutishness, caddishness, coarseness, crudeness, discourteousness,
   discourtesy, gross behavior, grossness, ill breeding, ill manners,
   impoliteness, inconsiderateness, indecorousness, indecorum,
   insensitivity, inurbanity, loutishness, mannerlessness,
   misbehavior, offensiveness, philistinism, rudeness, savagery,
   savagism, tactlessness, troglodytism, uncivilizedness,
   uncourtliness, uncouthness, uncultivatedness, uncultivation,
   unculturedness, ungallantness, ungentlemanliness, ungraciousness,
   unmannerliness, unpoliteness, unrefinement, unsolicitousness,
   vulgarity, wildness