cratch

From Middle English cratchen, cracchen (“to scratch”), alteration of *cratsen (“to scratch”), from Old Norse *kratsa or Middle Low German kratsen, krassen (“to scratch”), both ultimately from Old High German krazzōn, crazōn (“to scratch”), from Proto-West Germanic *krattōn (“to scratch”), ultimately of uncertain, likely onomatopoeic origin, and/or derived from Proto-Indo-European *ger- (“to scratch, carve, cut”). Cognate with Icelandic krota (“to engrave”). Compare also Icelandic krassa (“to scrawl”), Danish kradse (“to scratch, scrape, claw”), Swedish kratsa (“to scratch”), Dutch kratsen (“to scratch”), German kratzen (“to scratch”), and Albanian gërresë (“rasp, scraper”). Doublet of grate.

From Etymology 1.