It is likely that the word dude originated from quite an old English word – dudde. This was first used in England to refer to clothes – and often used in a joking way about clothes. This colloquial use was exactly the way the word dude was deployed for the first time on both sides of the Atlantic. In the 1870s due was used as an informal and somewhat negative term for an extremely well dressed dandy. Dude was a very common word in the 1880s for a man who was too well dressed for his own good. Very soon it became used for city slickers trying to make a show of themselves in the country.
It too almost 100 yeras for the meaning to change and lose any negative connotations. So much so that in the 1969 counterculture classic Easy Rider Peter Fonda explains the word to Jack Nicholson, “Dude means nice guy. Dude means a regular sort of person”.
By the 1980s “dude” had gone mainstream and was used as a standard form of address between male friends. In the 21st century it even entered the vocabulary of international diplomacy, with President George W. Bush occasionally addressing fellow leaders with the extremely casual “How’s it hanging, dude?” And during the same period Michael Moore famously co-opted the word in his lament for the lost values of American business and politics Dude, Where’s My Country.