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1.
When a person, either real or fictional, turns their baseball cap through 180 degrees so that the peak faces backwards to physically represent that they have switched into "go-time" mode.
I didn't think that nigga was serious til he southbilled that motherfucker.
by Silva2022 May 21, 2009
 
2.
To turn the hat 180 degrees to indicate that it is go-time or that shit is about to go down.
"You could tell that nigga was serious when he southbilled his hat."

"Southbill your hat, it's go time."
by anoonamoos May 21, 2009
 
3.
When a person, either real or fictional, turns their baseball cap through 180 degrees so that the peak faces backwards to physically represent that they have switched into "go-time" mode.
I didn't think that nigga was serious till he southbilled that motherfucker.
by SjHawkins May 20, 2009
 
4.
Term that refers to when a person, either real or fictional, turns their baseball cap through 180 degrees so that the peak faces backwards to physically represent that they have switched into "go-time" mode.

i.e Ash Ketchum from Pokemon
I didn't think that nigga was serious til he southbilled that motherfucker
by UpYourZ May 20, 2009
 
5.
Verb: to turn one's baseball cap 180 degrees, so that the bill is in the back, thereby showing how serious one is about whatever they are about to do.
"I thought that nigga was bluffin' till he southbilled on me. Nigga pulls a southbill, you KNOW shit be goin' down."

~The Dutchess of York
by PhilosophicalCAT May 20, 2009
 
6.
When a person, either real or fictional, turns their baseball cap through 180 degrees so that the peak faces backwards to physically represent that they have switched into "go-time" mode.
I knew some shit was about to go down when Ash southbilled his hat
by BillyTheMudkip May 20, 2009
 
7.
The act of turning the hat upon one's head 180 degrees so that the bill faces backwards.
You can tell when Jimmy is being serious when he southbills.
by Asterick May 21, 2009