Meaning

noun the capability to obliterate a target with more weapons (especially nuclear weapons) than are required

noun any effort that seems to go farther than would be necessary to achieve its goal

originEtymology tree Proto-Indo-European *úp Proto-Indo-European *-er Proto-Indo-European *upér Proto-Germanic *uber Old English ofer- Middle English over- English over- English kill English overkill From over- + kill.

Etymology from Wiktionary, CC BY-SA 3.0