To be obstructed from movement at normal speed by the presence of slow-moving African Americans intent on monopolizing the entire sidewalk, escalator, hallway, etc...
Similar in some respects to the Nightelf Mohawk from World of Warcraft that Mr. T rants about, except much more dangerous. A Blackadin is a Paladin with extremely gosu abilities. A Blackadin generally has a DPS range of "You gonna get raped," and an armor of "Nigga, pls."
A legion of blackadins marauded the crusaders from heaven. The blackadins channeled their power to devastating effect.
An onomatopoeia most likely first used by The Notorious B.I.G. in his 1994 debut album (Ready to Die) song, Gimme The Loot. It's used to describe the sound of a gunshot and/or the sound(s) heard in a fight such as, Boom, Pow, Blam, etc.
The Notorious B.I.G.: Man, niggas come through I'm taking high school rings too. Bitches get stripped down for they earrings and bangles and when I rock her and drop her I'm taking her door knockers, and if she's resistant Blakka! Blakka! Blakka!