shake on it/on something

shake on it

To confirm an agreement with someone by shaking hands. I can't believe he broke his promise to me after we shook on it and everything! I agree to the terms of this deal, so let's shake on it.
See also: on, shake
Farlex Dictionary of Idioms.

shake (hands) on something

to clasp and shake the hand of someone as a sign of agreement about something. The two people didn't sign a contract; they just shook hands on the terms of the agreement. I think it would be better to sign an agreement than just shake on it.
See also: on, shake
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

shake (hands) on it/on something

shake hands with somebody to show that you have made an agreement, a deal, etc: ‘OK, I’ll let the car go for $5 000.’ ‘Do you want to shake on it?’ Let’s shake on it.
See also: on, shake, something
Farlex Partner Idioms Dictionary

shake on

v.
To make some agreement binding by shaking hands: Our negotiations went well, and we soon shook on the deal. If you're satisfied with the arrangement, let's shake on it.
See also: on, shake
The American Heritage® Dictionary of Phrasal Verbs.
See also:
  • Is everything jake?
  • shake down
  • shake someone down
  • shakedown
  • (one's) knees are shaking
  • fling (one's) hands up
  • fling up (one's) hands
  • fling up (one's) hands in (some emotion)
  • fling (one's) hands up in (some emotion)
  • shook