Best definition
Derogatory word for a white person. First coined in the 1977 film Short Eyes.
Yakoo! Maker and creator of the devil. Swine merchant, your time is near at hand. Fuck with me and your time will be now. Your presence here affects the mind of my people like a fever. You Yakoo are the bearer of Nine thousand Nine hundred and Ninety Nine diseases, evil, corrupt pork chop eating atrocities…

– El Raheem in the film Short Eyes

yakoo: define #2
A name that all racists hate to be called. It is pronounced Yah-KOO. They think they have they right to call other people racial names (not to be listed), so they deserve to be called this. They are yakoos.
Look at that damn yakoo hatin on everybody.
yakoo: define #3
derogatory term for white people invented by Chris Rock on SNL