n.
- Destructive nuclear capacity exceeding the amount needed to destroy an enemy.
- Excessive killing.
- An excess of what is necessary or appropriate for a particular end: "government overkill in dealing with dissent" (Jesse Unruh).
To destroy (an enemy or enemy target) with more nuclear force than necessary.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.