What is a synonym for duke?

Answer 1

There is no exact synonym, as each rank of the nobility is different. If you are the Duke of Westbury, for example, you are not therefore the Earl or Marquess of Westbury (though you may happen to be the Earl or Marquess of Somewhere Else in addition to being Duke of Westbury).

Aside from the rank of nobility, the word 'duke' is also a slang term used in a couple of different ways. One is as a synonym for feces, or any other term referring to feces. The other is a fighting term, specifically boxing, bare knuckle or otherwise. For example: "Put up your dukes," would mean to raise your fists in preparation to fight/box. To "duke it out," would mean to fight about something. Your 'dukes' means your fists specifically.