keep one's nose clean

keep (one's) nose clean

To behave properly; to stay out of trouble. You better keep your nose clean, kid, or you're going to run into trouble you can't handle.
See also: clean, keep, nose

keep one's nose clean

Stay out of trouble. For example, Dad told Brian to keep his nose clean from now on or he'd cut off his allowance. [Colloquial; late 1800s]
See also: clean, keep, nose