Gaelic Mac Dhuibh "son of Dubh," literally "black."
Examples from the Web for macduff
The late Lord Hailes gives it as his opinion, that the indulgence was only to last till the tenth generation from Macduff.Minstrelsy of the Scottish Border Volume III (of 3)|Walter Scott
Then the rest of us drove over to Fyvie and caught the train to Macduff.The Mystery of the Sea|Bram Stoker
The same may be said of the destruction of Macduff's family.Characteristics of Women|Anna Jameson
Too well is she aware of the cause, and the consequence, of Macbeth's sending after Macduff; but she ventures not to hint.Bentley's Miscellany, Volume II|Various
While Ponsonby was roaring for his carriage the host rushed back to MacDuff's side.The Wood Fire in No. 3|F. Hopkinson Smith