Smoking gun | originally
The term “smoking gun” was originally, and still primarily is, a reference to an object or fact that serves as conclusive evidence of a crime or similar act. In addition to this, its meaning has evolved to uses completely unrelated criminal activity: for example, scientific evidence that is highly suggestive in favour of a particular hypothesis is sometimes called smoking gun evidence. Its name originally came from the idea of finding a smoking (i.e. very recently fired) gun on the person of a suspect wanted for shooting someone, which in that situation would be nearly unshakable proof of having committed the crime.
See also
- The Smoking Gun (Web site)
- Burden of proof
- Watergate scandal