The Collaborative International Dictionary of English v.0.48:

Crassness \Crass"ness\ (kr?s"n?s), n.
   Grossness. [Obs.] --Glanvill.
   [1913 Webster]

WordNet (r) 3.0 (2006):

crassness
    n 1: the quality of being crass--devoid of refinement [syn:
         crassness, crassitude]