Take a powder!

Scram! This tough-guy phrase came from the days when a ladies' bathroom was euphemistically called the powder room, the place where women went, among other reasons, to apply makeup. As gangster movies would have us believe, a lady's escort who wanted to discuss a matter in privacy with another gent told her to “take a powder.” Similarly, a genteel way to say you were going to the ladies' room was “I'm going to powder my nose.”