An expression used to challenge a person to commit an action.
Appropriate responses are as follows:
In agreement to do the action = "Who Won't?"
Not in agreement to do the action = "You right"
Absolutely not in agreement to do the action = "Are you dumb?"
To counter challenge = "YOU won't!"
When used in an overly serious manor "you won't" may be interchangeable with "You will not!"
Warning: Increased use of alcohol can and will cause excessive repetition.
Person 1: "You won't do jam and night." Person 2: "Who won't?! YOU won't!"