As used in modern urban conversation, the term refers to a white person who tries to emulate black people in order to appear hip or ghetto.
See also: wigger
Any 15-year old teenage white male who wears his pants down around his knees, wears a sports jersey and gold jewelry, and insists on blaring rap music at all hours of the day and night is a wannabe.
Also, any white person attempting to say something like fo' shizzle my nizzle.
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