Just launched! Learn slang while watching funny vids: urbandictionary.tv
1. my boo
Your boyfriend/girlfriend.
"Dat's my boo your messin' wit!"
2. my boo
Unfortunate pet names for a vagina. Especially one of those really scary looking vaginas, or one in an ill state of health. Like Leatherface's botched first attempt at making a skin suit.
My boo is looking busted right now but I'm hoping by tomorrow I'll be better.