Meaning
A piece of evidence so direct that it settles a question at a glance - the memo with the guilty sentence, the ledger that matches the denial. The phrase is reserved for conclusive proof rather than suspicion, and it thrives in political scandal, fraud cases, and disputes over documents. Reserve it for direct proof; suggestive evidence is not a smoking gun, and conceding that one may never be found is often the honest assessment. Regional use: General English (detective-fiction origin, American popularisation).
Origin
The image comes from detective fiction: a weapon still smoking when found in a suspect's hand is proof it was just fired. Arthur Conan Doyle built a scene on exactly that logic in 'The Adventure of the Gloria Scott' (1893), in which a chaplain 'stood with a smoking pistol in his hand' beside the accused. The condensed form 'smoking gun' became standard in twentieth-century English, and Watergate made it inescapable: the tape of Nixon and Haldeman talking on 23 June 1972, released on 5 August 1974 after the Supreme Court ordered it, caught the pair planning to deflect the FBI's Watergate inquiry - proof the president knew of the cover-up from the start - and was instantly and permanently labelled 'the smoking-gun tape'. Nixon resigned within days. Usage has since stretched to science and statistics, where a 'smoking gun' result confirms a hypothesis outright.
Research Sources
References used to check this entry’s meaning, history, or documented forms.
Variants
- a smoking pistol (original form)
- smoking gun
- smoking-gun evidence
- the smoking gun
Usage Examples
- Prosecutors lacked a smoking gun until the ledger turned up in the storage unit.
- The emails were suggestive, but the audit trail was the smoking gun.
- Investigators warned the committee that a smoking gun might never exist, and circumstantial evidence would have to carry the case.