1 definition by FlabergastABitch

Post Up

To incite a fight, or to call someone out.
used when people are mad and desire confrontation.

Girl:(Greg) Dude you look like Justin Beiber!
Greg:awh, thanks,(:
Jim: Greg, what a fag,
Greg:Post Up then bitch!

by FlabergastABitch September 16, 2010