What is the origin of the idiom "have a nerve" and when to use it?

The origin of the idiom "have a nerve" is not precisely documented, but it has likely been in use for many years in the English language. The phrase is likely derived from the idea that nerves are associated with feelings and sensations, including the sensation of fear or anxiety. It is used to describe someone displaying audacity, boldness, or impertinence in a particular context.