yo-boy, n. — Green’s Dictionary of Slang

yo-boy n.

[his use of the common black greeting yo! excl. (2)]

(US black) a white youth who apes his black contemporaries.

1991		D. Simon Homicide (1993) 562: We gotta try and find a yo boy named Moriarty.
2001		N. Green Shooting Dr. Jack (2002) 152: You been buying crack for the yo boys?