Origin uncertain. 1. In at least some cases it seems to be a variant of Irish Duffy. 2. Perhaps a variant of South German Tüffer, a habitational name for someone from Tüffen in Switzerland or Tiefen (earlier Tüeffen) near Freiburg, place names based on Old High German tiufī ‘gorge’ or tuf, taf ‘bog’, ‘swamp’. Compare Duffner. 3. Possibly an altered spelling of French Dufer, a nickname from du fer ‘(man) of iron’.