Best definition
Who you with? or Who you wit?
Used to ask one which gang and/or group the associate with. Much more “gangsta” then “Who are your friends?” Used

at the beginning of every episode of The Bernie Mac Show and in one episode can be seen embroidered on the back of Bernie’s maroon, velvet outfit.

Who you with? or Who you wit? example:

Bernie Mac walks on stage;

Bernie (to crowd): Who you wit?

Crowd (to Bernie, all together): Who you wit?

This dialogue continues until Bernie actually starts his act, however unfortunatelly for both parties neither found out who the other was “wit” and the question “Who you wit?” goes unanswered for all of eternity.