Anyone who has children with someone of a different race. All in all, a step in the right direction. White culture has always had issues with miscegenation, due to the racist pseudo-science of the 19'th century, which sought to prove the white man's superiority over the black. Fortunately, now that that mind set is beginning to fade, people are no longer classifying each other by race. The obsession to keep the race "pure" is ideaological garbage laced with putrid racism.
Racists claim that a miscegenist "muddies" their pure Aryan bloodline. I say it muddies an otherwise functional mind to ponder why skinheads still don't have a clue what Aryan means.
An ignorant person willfully engaging in race mixing/muddying
That white ho caught the jungle fever and is now a miscegenist.