Let sleeping dogs lie Definition 1 of 1Pro Tip 1/3Potential Trouble Use when acknowledging that action might create conflict or problems. They stopped arguing, so let's let sleeping dogs lie. Pro Tip 2/3No Benefit Suggests that taking action is pointless and best avoided. He didn't remember the mistake, so I let sleeping dogs lie. Pro Tip 3/3Subtle Warning Implies a warning to be cautious not to awaken hidden issues. She's calm now, but push further and you won't be letting sleeping dogs lie.