informal A shortening of "you know what."
1. Used to introduce some piece of information one believes the other person does not know. Hey, know what? If you eat all your vegetables, you can have a brownie after dinner! A: "Psst, Tom! Know what?" B: "What?" A: "Sarah has a crush on you!" B: "Huh? Really?"
2. A phrase used to convey a sudden decision or realization. A: "Want to come to a party with us?" B: "Well, I was going to study tonight… Hey, know what? Yes, I will come with you. I need a break."
3. A rhetorical question posed before a statement one considers to be the blunt truth, often during an argument or heated exchange. A: "I'm sorry Janet, it's not you, it's me." B: "Know what, John? You're right—you are the problem!"
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.