barking mad

What is the origin of the idiom "barking mad" and when to use it?

The origin of the idiom "barking mad" likely stems from the behavior of dogs. Dogs often bark excessively, especially when they are agitated or displaying erratic behavior. The word "mad" in this context refers to a state of insanity or irrationality. Combining "barking" with "mad" creates a colorful and vivid expression to describe someone or something as being irrational, eccentric, or exhibiting unusual behavior. It is often used to express a sense of disbelief, amusement, or disapproval towards actions or ideas that deviate from the norm.