loose cannon

1. 1.

   a person who is expected to perform a particular task but who is out of control and dangerous

   Broaderperson

Questions about loose cannon

What does loose cannon mean?

loose cannon means "a person who is expected to perform a particular task but who is out of control and dangerous".

Is loose cannon a common word?

loose cannon 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.