smoking gun

American  

noun

1. indisputable proof or evidence of a crime.

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smoking gun British  

noun

1. a piece of irrefutable incriminating evidence

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smoking gun Idioms  

1. Something that serves as indisputable evidence or proof, especially of a crime. For example, There is no smoking gun in the Oval Office; the President had no role in tampering with the evidence. This expression alludes to the smoke coming from a recently discharged firearm, a normal occurrence until the invention of smokeless powder. [Mid-1900s]

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Etymology

Origin of smoking gun

First recorded in 1970–75

Example Sentences

See Examples For:

smoking gun

Then came what appeared to be the evidentiary smoking gun: a lettuce sample that tested positive for Cyclospora.

From Salon ● Sep. 13, 2026

Hardly the smoking gun that puts him in an Afghan cave, scheming with Osama bin Laden.

From Los Angeles Times ● Sep. 3, 2026

Their view is that they haven't been shown a smoking gun, and therefore they want Andy Burnham to see if it's possible to overcome any security concerns he has.

From BBC ● Aug. 12, 2026

Now, I think Joseph has found the smoking gun," Howell continued, "and he's tied the bumps into the magnetar model, and explained everything with the best-tested theory in astrophysics -- General Relativity.

From Science Daily ● Mar. 11, 2026

The tape of Nixon and his staff plotting to use the CIA to block the FBI’s investigation of the Watergate break-in proved to be the smoking gun prosecutors were looking for.

From "Most Dangerous: Daniel Ellsberg and the Secret History of the Vietnam War" by Steve Sheinkin