war crime

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various crimes, such as genocide or the mistreatment of prisoners of war, committed during a war and considered in violation of the conventions of warfare.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun law A punishable offense, under international law, for violations of the law of war by any person or persons, military or civilian.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a crime committed in wartime; violation of rules of war