Ofay | Slog | The Stranger, Seattle's Only Newspaper:
Nobody knows where "ofay" comes from, but a few guesses. From the Online Etymological Dictionary:
Amer.Eng. black slang, "white person," 1925, of unknown origin. If, as is sometimes claimed, it derives from an African word, none corresponding to it has been found. Perhaps the most plausible speculation is Yoruba ófé "to disappear" (as from a powerful enemy), with the sense transf. from the word of self-protection to the source of the threat. OED regards the main alternative theory, that it is pig Latin for foe, to be an "implausible guess."
Another theory is that the Yoruba ófé was spoken to make the white person disappear. It also might come from the Ibibio word "afia," which means "light-colored."