streetkid or gangsta
(and associated styles of speech and dress)
Que ceba, ese ñero se pegó el chicle detrás de la oreja.
Gross, that bum just put his gum behind his ear.
Origin: comes from what people on the street supposedly call each other — ñero, short for compañero.
Related: cani (Spain), naco (México), turro (Argentina).
See also: this entire website about how to recognize a ñero.