get (one) off the hook

1. To help one to avoid punishment or culpability for some wrongdoing. He's the best lawyer in the business. If anyone can get you off the hook for murder, he can. Can you please tell Mom that you broke the vase and get me off the hook? I thought my own brother would try to get me off the hook—not turn me into the police!

2. To free one from the responsibility of some task; to help one to avoid some obligation or duty. Thank you for getting me off the hook for Saturday—I was dreading having to babysit at 6 AM on my day off! I knew Uncle Al would just talk incessantly about the weather all night, so I got you off the hook. You're now sitting with us at the other end of the table. Mom, can you please write a note and get me off the hook for this dumb field trip?

get somebody off the ˈhook

(informal) help somebody to avoid punishment, etc: You’re going to need a very clever lawyer to get you off the hook.

off the hook, to get/to be let

To escape from some difficulty. The analogy is to throwing a fish one has caught back into the water, saving its life. The term on the hook goes back to the seventeenth century; the current cliché dates only from the mid-1800s. Anthony Trollope used it (The Small House at Allington, 1864): “Poor Caudle . . . he’s hooked, and he’ll never get himself off the hook again.”