let (somebody) off = let someone go without punishment
examples:
- I 'll let you off this time but next time be more careful.
- We can 't just let him off. It 's not the first time we 've caught him stealing.
- I 'll let you off with a warning now but if you drive your motorcycle without a helmet next time I will drive you to the traffic police myself!
- They let him off lightly because he was only twelve years old.
- The Court was very lenient. They let him off.
- The traffic police let him off with just a fine for driving drunk. If you ask me, they should have removed his number plate. He was let off lightly, wasn 't he?
- The boss let me off this time but said that if I ever make the same mistake, he 'll fire me.
