Source : Webster's Revised Unabridged Dictionary (1913)

Barbarousness \Bar"ba*rous*ness\, n.
   The quality or state of being barbarous; barbarity;
   barbarism.

Source : WordNet®

barbarousness
     n : the quality of being shockingly cruel and inhumane [syn: {atrocity},
          {atrociousness}, {barbarity}, {heinousness}]