A masher. One who renders himself conspicuous by affectation of dress, manners, and speech. The word was first familiarised in London in 1881, and is a revival of the old word dudes (clothes). We have several derivations, as dudder, one who sells dress-pieces; duddery, a rag-shop; duddle, to wrap up warmly (Halliwell), etc. It is not of American origin.
“I should just as soon expect to see Mercutio smoke a cigarette, as to find him ambling about the stage with the mincing manners of a dude.” —Jefferson: Century Magazine, January, 1890, p. 383.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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