'atrocity' definitions:

Definition of 'atrocity'

(from WordNet)
noun
The quality of being shockingly cruel and inhumane [syn: atrocity, atrociousness, barbarity, barbarousness, heinousness]
noun
An act of atrocious cruelty [syn: atrocity, inhumanity]

Synonyms of 'atrocity'

From: Moby Thesaurus