The term put up your dukes is an idiom that was first used in the mid-1800s. An idiom is a figure of speech that is a word, group of words or phrase that has a figurative meaning that is not easily deduced from its literal definition. We will examine the definition of the phrase put up your dukes, where it most probably came from and some examples of its use in sentences.
Put up your dukes is an admonition to get into a fighting stance and defend yourself. In this case, the word dukes is slang for hands. Though some believe that the phrase put up your dukes is related to the Romany word dook meaning a hand that is read in palmistry, the origin is most probably rhyming slang, also known as Cockney rhyming slang. This is a method of speaking in which rhyming words become substitutions for conventionally used words. In this case, the Duke of Yorks was substituted for the word forks. At the time, forks was a slang term for fingers. The word duke came to take on the meaning of the slang term forks, which in turn was slang for fingers or hands. While this explanation seems rather convoluted, it is the most agreed-upon explanation of the origin of the idiom put up your dukes.
Examples
Put up your dukes and fight your way into the world of Winning. (The Chicago Tribune)
A New Jersey man picked a fight with his girlfriend’s 2-year-old son, telling the defenseless toddler to put up his dukes before allegedly beating him to death. (The New York Post)
However, it is quite another to put up your dukes as Malcolm does and demand:What side are you on? (The New York Review of Books)