Avoid disturbing or bothering someone, as in It's best to leave Dean in peace when he's paying the bills. This expression uses peace in the sense of "undisturbed," a usage dating from the early 1200s. Also see leave one alone; let be.

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Company. All rights reserved.