ph.

Subways Urban Railways-(地铁和市区铁路)

1. 准许…不必做（或不必工作）
If someone in authority lets you off a task or duty, they give you permission not to do it.

2. 对…宽大处理
If you let someone off, you give them a lighter punishment than they expect or no punishment at all.

3. 使（炸药等）爆炸；开（枪、炮等）
If you let off an explosive or a gun, you explode or fire it.

1. grant exemption or release to

e.g. Please excuse me from this class

Synonym: excuserelieveexempt