Mary Mapes Dodge, editor of St. Nicholas Magazine, muddied the waters a little in 1890 when she wrote in an article about curious words:
The word dude began to mingle in the speech of the people of this country about the year 1873, but did not make its appearance in print until 1876, when it boldly met the public gaze in the February number of “Putnam’s Magazine.” The origin of the word has been a question ever since it asserted itself in every-day speech, and its claim to represent a human nonentity in raiment befitting either fool or fashion-plate has never yet received the stamp of authority.In fact, Putnam’s Magazine wasn’t being published in 1876. The issue at issue was dated February 1870. Furthermore, that magazine didn’t include the word “dude”; it included the word “dud,” with the direct opposite meaning.
That issue of Putnam’s included part of a novel titled Eirene: or, A Woman’s Right, by Mary Clemmer. In it someone asks a young man what he thinks of a young lady, and he replies:
“Think! I think she is dressed like a dud. Can’t say how she would look in the costume of the present century.”Maximilian Schele De Vere quoted that passage (without exacting accuracy) in his Americanisms: The English of the New World (1871) under the entry “Dud.” Context shows it was a form of the old word “dowd,” as in “dowdy.” It meant a woman unfashionably dressed and not a man too fashionably dressed.
After “dude” burst on the scene in 1883, however, etymologists went looking for its origin. Some found De Vere’s entry and cited it in an argument that “dude” had grown out of “dud.” For discussion of a more convincing theory, see this posting at Boston 1775.