Source : Webster's Revised Unabridged Dictionary (1913)

Inhumanity \In`hu*man"i*ty\, n.; pl. {Inhumanities}. [L.
   inhumanitas: cf. F. inhumanit['e].]
   The quality or state of being inhuman; cruelty; barbarity.

         Man's inhumanity to man Makes countless thousands
         mourn.                                   --Burns.

Source : WordNet®

inhumanity
     n 1: the quality of lacking compassion or consideration for
          others [syn: {inhumaneness}] [ant: {humaneness}]
     2: an act of atrocious cruelty [syn: {atrocity}]