The phrase "When the cat's away, the mice will play" means that when a person in authority or a supervisor is not present, the people under their control or supervision will behave badly, misbehave, or take advantage of the absence to do as they please. It implies that without oversight, people tend to break rules or act more freely, often in a way that is less disciplined or orderly than when being watched. This proverb has existed for centuries and originates from a medieval Latin saying that translates roughly to "When the cat sleeps, the mouse leaves its hole, rejoicing." It has equivalents in many languages and has been used in English since around the 15th century, even appearing in Shakespeare's works. The phrase is often used in everyday contexts such as children misbehaving when a teacher leaves the room, employees slacking off when the boss is away, or any scenario where absent authority leads to relaxed or unruly behavior. People also frequently shorten it to just "While the cat's away," with the second half implied. In summary, it is a metaphor about the natural behavior of subordinates or those supervised taking liberties during the absence of a controlling presence.
