Question 1

What does "let sleeping dogs lie" mean?

Accepted Answer

To avoid bringing up a past problem or controversy that could cause trouble if disturbed.

Question 2

How do you use "let sleeping dogs lie" in a sentence?

Accepted Answer

He wanted to apologise, but his friends advised him to let sleeping dogs lie.

Question 3

Is "let sleeping dogs lie" formal or informal?

Accepted Answer

"let sleeping dogs lie" is register-neutral — appropriate in both casual and formal contexts. Used to advise against reopening old disputes or sensitive issues that have been forgotten.