The act of shifting a motor vehicle into reverse gear while on a highway in order to back up and to get onto an exit ramp one has already passed. This term comes from the New York Metro area, where Asians and Caucasians have conducted a nonscientific study by looking to see what the person taking this action looked like only to find that they are black at least 90% of the time.
by ISwearIMnotRacist June 10, 2013

the traffic caused by a group of African Americans blocking the hall and preventing Caucasian students from moving to their next class.
Tom: Dude, why arent we moving?????
Andrew: Man this is the Math hall. This is probably the black-up from all those black guys who walk slowly.
Andrew: Man this is the Math hall. This is probably the black-up from all those black guys who walk slowly.
by FlockaFlocka12 February 22, 2011

After Joe made a racist joke at KFC, he soon drew a crowd and was blacked up on the spot. His friends claimed they never knew Joe in order to avoid being blacked up.
by Nevets December 15, 2007

An act of aggression that occurs "when fools need a beating, and you call your homies, and put in some work."
by Rihanna had it coming January 24, 2011

by AzraelNarianErnee September 18, 2013

A black up plan can only be observed.
"What the hell, you're 2 weeks pregnant?!? Where's my boxing gloves."
"What the hell, you're 2 weeks pregnant?!? Where's my boxing gloves."
by bpiau2728 March 8, 2012

by LukeAndShet November 29, 2010
