تعريف ومعنى "{one's} [head] off"

What is the origin of the idiom "one's head off" and when to use it?

The origin of the idiom "one's head off" is rooted in the idea of someone speaking or singing so loudly that it feels as if their head might come off. This expression is commonly used in both spoken and written English to refer to someone speaking or singing very loudly or with great enthusiasm. It suggests that the person is using their voice to its maximum capacity.