Cognomen Duj (Duj 
) , across the world, is a rare last name. The family name Duj is habitual in Western Europe, particularly Belgium, where it is a rare surname, France, where it is a very rare surname, and Germany. Not in comparison with a country's population, it most frequently occurs in Indonesia, France, and Germany. Much more frequently, Duj is the forename as well as the last name.