look up any word, like darude - sandstorm:
 
3.
1: The theory that, once you are friends with one black person (in school, work, etc.), you are friends with the rest of them by association. 2: A group of black friends that, although they never hang out with you, will instantly have your back if you get into a fight.
Girl 1: Did you hear that I made fun of Rebecca's hair this morning?
Girl 2: You did what?! She's head cheerleader! They're all gonna kick your ass now!
Girl 1: Nah, I'm friends with Tawanda, the captain of the girls' basketball team. I've got blackup.

OR

Guy 1: Why don't you come say that to my face, man?!
Guy 2: Dude, I don't wanna fight you-
Guy 3, 4, 5, & 6: Yo! You got a problem, dog? What up? You wanna go?!
Guy 2: Where did you guys come from?
Guy 3: Hey, man, we yo blackup!
by Røse December 23, 2008
 
1.
When you're outnumbered in a fight, and so you call in black people for the win.
Shit, there's 10 of them waiting for us in the park! Call for blackup!

"When the War on Terror gets tough, you call for blackup. Barack Obama 2008!"
by Harrr February 12, 2007
 
2.
The calling in of nigras for extra assistance.
The pool is open, call for blackup!
by Anon E m us August 31, 2007
 
4.
African American back up
i was bein' mugged, 'till my black up arrived
by Aram September 27, 2007
 
5.
To light up and smoke herb made for man
(and woman too!);Jamaican.
Hey mon,let's go to the garage and black
up with some sugga shack. Seen?
by Scroter Anderskin February 22, 2005
 
6.
Detroit slang for a group of African-American police officers who support or reinforce a group of white police officers.
Two white cops are writing a parking ticket outside a night club when a dozen black men rush out the door yelling and fighting one another. The cops immediately call for help on the radio. Minutes later, two cop cars with four big, black cops arrive.

Observer 1: "Wow, those white cops were in over their heads."
Observer 2: "Yep. That's why they called for blackup."
by michiganessay June 06, 2011
 
7.
To get high.
Generally off marijuana smoke.
'hey man what you doin after this?'

'yo ma breda i tink ima go home n black up some more you kno?''
by Lil West February 02, 2010