The term referring to someone who is another person's bf/gf on the side.
Guy 1: Man what are you going to do when your girl is out of town?
Guy 2: Don't worry I got my availaboo!

or

Girl 1: If my man don't wanna go to the club I will just go call my availaboo.
Girl 2: I'm always callin' my availaboo.

or

Shaniqua: Girl, I just found out that I'm just his availaboo!
by Reg Money June 13, 2008
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