Mac Duibh
Mac DUIBH—IV—M'Duffe, MacDuff, Duff, and, by translation, Black; 'son of Dubh' (an Irish personal name meaning 'black'). Besides the Irish families bearing this surname, there is a Scottish clan Mac Duibh, of which the old Earls of Fife were the heads. See Mac Dhuibh.
Alphabetical Index to Irish Surnames