To get off scot-free means to escape punishment or consequences entirely, even though you probably deserved some. When someone gets away scot-free, they walk away from trouble without paying any price at all.

If two students get caught throwing paper airplanes in class, but only one gets detention while the other somehow avoids any consequence, that second student got off scot-free. When a player commits an obvious foul in soccer but the referee doesn't see it, they got away scot-free.

People often use this phrase with a slight tone of unfairness, suggesting that someone should have faced consequences but didn't. If your sister breaks a lamp and somehow your parents never find out who did it, she got away scot-free. The phrase captures that frustrating moment when someone avoids the accountability they deserved.