A: Andrew’s late again.

B: Really? He’s doing all right, I think.

A: Cut him some slack. His wife just had a baby.

Note: Originally “cutting sb. some slack” was used in several contexts — naval, for letting out on a rope; workmen in trees or on tall building, for similarly letting out rope; and horsemen, for loosening the reins. When used on people, this slang refers to not judging someone as severely as you usually would because they are having problems at the present time or being less demanding of someone.