Definition from Wiktionary, the free dictionary
- (literally) A destructive capacity that exceeds that needed to destroy an enemy; especially with nuclear weapons.
- (idiomatic) An unnecessary excess of whatever is needed to achieve a goal.
- 24 hours of TV coverage of the US election verged on overkill.
- Should I give you yet more homework, or would that be overkill?
an unnecessary excess of something (idiomatic)
- (transitive) To destroy something with more (nuclear) force than is required.