or croppy, subs. (old).Originally applied to criminals CROPPED as to their ears and their noses by the public executioner; subsequently, to convicts, in allusion to their close CROPPED hair; hence to any person whose hair was cut close to the head; e.g., the Puritans and the Irish Rebels of 1789.
1870. SIR G. C. LEWIS, Letters, p. 410. Wearing the hair short and without powder was, at this time, considered a mark of French principles. Hair so worn was called a crop. Hence Lord Melbournes phrase, crop-imitating wig (Poetry of the Anti-Jacobin, p. 41]. This is the origin of CROPPIES, as applied to the Irish rebels of 1789.
187779. J. R. GREEN, A Short History of the English People, ch. x., The CROPPIES, as the Irish insurgents were called in derision from their short-cut hair.