The original usage has been supplanted and the term is actually a friendly joust used to describe the state of being a random, anonymous, unrecognizable person of African descent.
It's counterpart for white people is Wigga or Wigger.
*OUT OF NOWHERE! AN INCOGNEGRO!*
-Death Ensues shortly after-
2) a term describing when African-Americans become anonymous because others are unable to distinguish between them.
2)My English Teacher: Alyson, you said you wanted to ask me a question?
Alyson: Uhh, no.
Me: That was me.
My English Teacher: <flustered> Uh, sorry.
This will usually apply to dress, speech and mannerisms. There will be very limited use of urban slang and pant sagging. Nerdy glasses will usually be part of the attire.