rascalyoudaoicibaDictYouDict[rascal 词源字典]
rascal: [14] Rascal has been traced back ultimately to Latin rādere ‘scratch’. Its past participial stem rās- (source of English erase and razor) formed the basis of a Vulgar Latin verb *rāsicāre. From this was derived the noun *rāsica ‘scurf, scab, dregs, filth’, which passed into Old Northern French as *rasque (its central Old French counterpart, rasche, may be the source of English rash).

And it could well be that this *rasque lies behind Old French rascaille ‘mob, rabble’, which gave English rascal (the English word originally meant ‘rabble’ too, but the application to an individual person emerged in the 15th and 16th centuries). Rapscallion [17] is an alteration of a now defunct rascallion, which may have derived from rascal.

=> erase, rapscallion, rash, razor[rascal etymology, rascal origin, 英语词源]
rascal (n.)youdaoicibaDictYouDict
mid-14c., rascaile "people of the lowest class, rabble of an army," also singular, "low, tricky, dishonest person," from Old French rascaille "rabble, mob" (12c., Modern French racaille, "the rascality or base and rascall sort, the scumme, dregs, offals, outcasts, of any company" [Cotgrave, French-English Dictionary, 1611]), perhaps a diminutive from Old French rascler, from Vulgar Latin *rasicare "to scrape" (see rash (n.)). Used also in Middle English of animals not hunted as game.