smoking gun

1. 1.

   indisputable evidence (especially of a crime)

   Broaderevidence

Questions about smoking gun

What does smoking gun mean?

smoking gun means "indisputable evidence (especially of a crime)".

Is smoking gun a common word?

smoking gun is banded "Rare" — specialist or archaic — most readers will not have met it. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.