rash

The adjective is derived from Middle English rash, rasch (“hasty, headstrong, rash”) [and other forms], probably from Old English *ræsċ (“rash”) (found in derivatives such as ræsċan (“to move rapidly; to flicker; to flash; to glitter; to quiver”), ræsċettan (“to crackle, sparkle”), etc.), from Proto-West Germanic *rask, *raskī, *rasku, from Proto-Germanic *raskaz, *raskuz, *raþskaz, *raþskuz (“rash; rapid”), from Proto-Indo-European *Hreth₂- (“to run, roll”). The Middle English word was probably influenced by the cognates listed below.

The adverb is derived from Middle English rashe (“quickly, rapidly”), from rash, rasch (adjective) (see above).

Probably from Old French rasche, rache (“skin eruption, rash; (specifically) scabies, scurf”) (obsolete), from racher (“to scrape; to scratch”) (although this is only directly attested later than the noun), from Vulgar Latin *rāsicāre (“to scrape”), from Latin rāsus (“scraped, scratched; shaved”), the perfect passive participle of rādō (“to scrape, scratch; to shave; to rub, smooth; to brush along, graze”). Doublet of rase and raze

Uncertain; the word is similar to other words from Germanic or Romance languages listed in the table below, but the connection between the English word and those words is unclear. One suggestion is that they ultimately derive from the town of Arras in France, known for its cloth and wool industries (whence arras (“tapestry, wall hanging”)); compare German Rasch (“lightly woven silk or (usually) worsted fabric”) (said to be from Middle High German arrasch (“arras”), and ultimately from the name of the town), and the obsolete names for the fabric, Catalan drap de arraz, drap d'Arraç, Spanish paño de ras (literally “cloth of Arras”). The Oxford English Dictionary states that even if rash did not originally derive from Arras, the name of the town could have influenced the English word.

Imitative.

From Late Middle English rashen, rassh (“to hasten, hurry, rush”) [and other forms], from Old English ræscan (“to move rapidly; to flicker; to flash; to glitter; to quiver”); see further at etymology 1.

Probably an aphetic form of arace (“to tear up by the roots; to draw away”) (obsolete), from Middle English aracen (“to remove (something) by force, pluck or pull out, tear out; to grab; to lacerate; to flay or skin (an animal); to erase, obliterate”) [and other forms], from Old French aracer, arachier (“to pull off (by physical force)”) [and other forms] (whence Anglo-Norman racher, aracher (“to pluck out, pull out”); modern French arracher (“to pull up, tear out, uproot; to extract, take out (a tooth); to peel, pull off, rip off; to buy, snap up; to fight over; to tear (oneself) away from”)), a variant of esrachier (“to eradicate, get rid of”), from Latin exrādīcāre, ērādīcāre (“to root out; to annihilate, extirpate”), from ē- (a variant of ex- (prefix meaning ‘away; out’)) + rādīx (“root of a plant”) (ultimately from Proto-Indo-European *wréh₂ds (“root”)) + -ō (suffix forming regular first-conjugation verbs).