off the hook 是一个美国常用的习惯用语，是从钓鱼衍变而来来的，最早的时候是指一条本来已经咬钩的鱼又脱了钩，重获自由。从字面看hook是钩子的意思，所以，Off the hook 脱钩，其实就是脱身，或是摆脱责任的意思。
例句：
1.We have confirmed that the man was two thousand miles away in Los Angeles at the time of the murder, sir. So as far as we're concerned, he is off the hook, and no further investigation is required.
我们已经证实，谋杀案案发的时候，此人正在两千英里以外的洛杉矶市，所以对于我们来说，他不可能参与此案。不再需要对他进行调查了。
2.I agree with the mayor that many of our problems can be blamed on the policies of the federal government, but I also think that the mayor has to take some of the blame himself. There's no way he should be let off the hook so easily.
我同意市长的看法，我们遇到的很多问题确实要归咎于联邦政府的政策，不过我觉得，市长也应该承担一部分责任，绝不能让他这么轻松地推卸责任。
