ofay
rather outdated Black English for "foe," origin unknown. See page 26 of the 1971 Bantam edition of Ann Fairbairn's novel Five Smooth Stones, where one of the African American characters, Geneva, defines it as meaning "foe" but gives no hint of etymology.  I'd be tempted to go with the African origin.
Don't we know she a ofay _____?  derogatory having to do with sexual conduct.

He just an ofay, that what he be. 