Dude is American slang for an individual, typically male. From the 1870s to the 1960s, dude primarily meant a male person who dressed in an extremely fashionable manner (a dandy) or a conspicuous citified person who was visiting a rural location, a "city slicker". In the 1960s, dude evolved to mean any male person, a meaning that slipped into mainstream American slang in the 1970s. Current slang retains at least some use of all three of these common meanings. History. The term "dude" may have derived from the 18th-century word "doodle", as in "Yankee Doodle Dandy".
https://en.wikipedia.org/wiki/Dude