Dandy. , Some one has endeavoured to deduce the etymology of this word from dandi-prat, a coin, as Rapin informs us, struck in the reign of Henry VII. It has been frequently applied as a term of contempt by the early dramatists. Thus Middleton, in his comedy ‘More Dissemblers besides Women,’ makes Dandolo say of Lactantio’s page, “there’s no fellowship in this dandiprat, this dive-dapper.” In the same play, Linquepace says, “Who would be plagued with a dandiprat usher,” &c. In Massinger’s Virgin Martyr, Hircius, speaking of the attendant of Dorothea, thus soliloquizes upon him: “The smug dandiprat smells us out whatever we are doing.” He has just before entitled him a “jackanapes,” a “white faced monkey,” and a “chitty-faced page.” Old Marston, in his ‘Scourge for Villanies,’ notices the dandiprats, and so does honest Master Dekker, in one of his comedies. The term seems to have been in common request in the age of Queen Elizabeth, as an epithet of reproach.

Quoted from: The London Literary Gazette and Journal of Belles Lettres, etc. No. 205, December 23, 1820: 830.