In basketball, it's a slam dunk performed by a nigga individual. This differs from both a white
guy and a black person in the usual behavioral ways. Some quintessential characteristics of the nigga dunk is when the nigga leaps at least 4 feet in the air with chest at
rim height, cocks the ball back, slams the ball into rim over some poor white
guy that attempted to block the
shot, then hangs on the rim and swings on it a couple of times. He then drops to the ground in an exaggerated manner, does a back flip, and then tears his shirt.
A nigga dunk is an antonym for a "white
guy dunk", also known as a rim grazer done by some 6'5 unathletic white
guy.