Noun or adjective. Racist term derived from the word sibling. The dark-skinned brother or sister of a caucasian--could be adopted or from a shared parent.
Larry: Who the hell is that little ninja?
Darryl: Oh, that's my adopted nigling Carlton. He's good for my parents' taxes.
Larry:What's up with the familial diversity?
Darryl: Momma hoed out for meth and ended up adding a little chocolate sauce to the vanilla ice cream--thus, I have two black nigling brothers and an asian nigling sister.