a/the smoking gun

smoking gun

Indisputably incriminating evidence. Likened to a gun that is still smoking after having been fired. A smoking gun was revealed in the form of emails documenting the man's involvement in the money laundering scheme. So far the prosecutor has presented only circumstantial evidence, but she's expected to reveal a smoking gun against the defendant soon.
See also: gun, smoking
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

the smoking gun

Fig. the indisputable sign of guilt. (Fig. on a murderer being caught just after shooting the victim.) Mr. south was left holding the smoking gun. The chief of staff decided that the the aide should be found with the smoking gun.
See also: gun, smoking
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

smoking gun

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]
See also: gun, smoking
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

a smoking gun

COMMON If you talk about a smoking gun, you mean a piece of evidence which proves that a particular person is definitely responsible for a crime. The search for other kinds of evidence failed to produce a smoking gun. First of all, there's no smoking gun. In the course of our investigation we did not find a single piece of evidence.
See also: gun, smoking
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012

a smoking gun (or pistol)

a piece of incontrovertible evidence.
This phrase draws on the assumption, a staple of detective fiction, that the person found with a recently fired gun must be the guilty party. The use of the phrase in the late 20th century was particularly associated with the Watergate scandal in the early 1970s involving the US President Richard Nixon . When one of the Watergate tapes revealed Nixon's wish to limit the FBI's role in the investigation, Barber B. Conable famously commented: ‘I guess we have found the smoking pistol, haven't we?’
1998 New Scientist This genetic smoking gun is evidence of a migration out of Asia that is hard to refute.
See also: gun, smoking
Farlex Partner Idioms Dictionary © Farlex 2017

a/the ˌsmoking ˈgun

something that seems to prove that somebody has done something wrong or illegal: This memo could be the smoking gun that investigators have been looking for.
See also: gun, smoking
Farlex Partner Idioms Dictionary © Farlex 2017

smoking gun

n. the indisputable sign of guilt. The chief of staff decided that the admiral should be found with the smoking gun.
See also: gun, smoking
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.

smoking gun

Definite evidence of illegal or criminal activity. The term alludes to smoke emitted by a revolver or other kind of gun that has been fired, but it is also used more broadly for other kinds of malfeasance. For example, Time (Sept. 19, 1977) had it, “In fact there may be no ‘smoking gun’—no incontrovertible black-and-white evidence of wrongdoing by Lance.” The New York Times (Oct. 3, 2004) quoted National Security Advisor Condoleezza Rice, talking on CNN about aluminum tubes in Iraq suspected to be used for nuclear weapons, “We don’t want the smoking gun to be a mushroom cloud.”
See also: gun, smoking
The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer
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