Definition & Meaning of "(as|) quiet as a mouse"

What is the origin of the idiom "quiet as a mouse" and when to use it?

The phrase "quiet as a mouse" is an idiomatic expression that compares the silence or lack of noise made by a mouse to a person or situation that is exceptionally quiet or silent. It likely originated from the observation that mice move discreetly and make very little noise. It is used to describe a person, place, or situation that is remarkably quiet or devoid of noise. It implies a state of tranquility or the absence of any audible disturbances.