Duff is an uncommon given name of Scottish origin, derived from the Scottish Gaelic word 'dubh', which means 'dark'. It has been used historically as both a first and last name in Scotland and Ireland. The name Duff is often associated with Irish and Scottish history, particularly through figures like Duff the Ugly (Dubh the Black), an 11th-century King of Scotland who was known for his bravery and military prowess. Despite its historical significance, Duff is not a name that has gained widespread popularity in modern times. Today, it is occasionally used as a given name but remains quite rare, perhaps due to its association with the Scottish word for 'smoke' or 'reek', which also shares the same etymology.
The name Duff experienced significant fluctuations in popularity over the years, with a marked increase from 1953 onwards.