'smoking gun' definitions:
Definition of 'smoking gun'
(from WordNet)
noun
Indisputable evidence (especially of a crime)
Definition of 'smoking gun'
From: GCIDE
- smoking gun \smok"ing gun`\ (sm[=o]k"[i^]ng g[u^]n`), n. [metaphorical] [from imagined situations where a person holding a pistol, still smoking from having been fired, is found standing over a dead person] Incontrovertible evidence; convincing evidence. [PJC]