The Collaborative International Dictionary of English v.0.48:

Impolite \Im`po*lite"\, a. [L. impolitus unpolishied, pref. im-
   not + politus, p. p. of polire to polish, refine. See
   Polite.]
   Not polite; not of polished manners; wanting in good manners;
   discourteous; uncivil; rude. -- Im`po*lite"ly, adv. --
   Im`po*lite"ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

impoliteness
    n 1: a discourteous manner that ignores accepted social usage
         [ant: niceness, politeness]