look up any word, like donkey punch:
 
1.
1. to get ready for a fight

2. to get in the fighting position
"Aye dawg! You betta square up cause I'm fittin to knock your ass out!"

"I squared up with that fool cause I thought he wanted to throw down!"
by jOhNnY bOi September 20, 2005
 
2.
to get ready to fight; get in the fighting position
Ay man be ready to square up wen dat fool comes down here!
by johnny boi September 10, 2005
 
3.
To settle a bill or debt. Square refers to the honesty of the deal, and up is the action of payment or performing the task.

To tighten the connections or correct the angles in a construction project, since squares are made of right angles at exactly ninety degrees, which is the majority of building connections and materials.

To confirm plans and reservations, straighten, or organize.
"When I come by tomorrow, I'll square up with you on the loan you gave me."

"If this drywall's gonna hang right, you better square up that door frame."

"I got my vacation all squared up."

"It's supposed to be in the seventies this weekend, so I'm gonna get the lawn squared up."
by Coell March 15, 2006
 
4.
The term "Square Up" is also used specifically by sex-trade workers (prostitutes of both sex) to describe "going straight" ie. retiring or otherwise getting out of the business to live a normal, "square" lifestyle (with spouse, kids, mortgage etc.) up off the street.
The hooker couldn't take the street life anymore so after one of her johns proposed marriage, she decided to square up.
by Jaxxon July 02, 2009
 
5.
To double up any that you are ordering or buying.

Waitress: Do you want a biscuit or hash browns with your cfs?

Person: Give me HBs (Hash Browns)...tell you what why don't you go ahead and square up them bitches...thug life bitch!
by Flo$$y B May 04, 2006