scrat.

From Middle English scratten. Further etymology uncertain; apparently related to cratch, from Middle English cratchen, cracchen (“to scratch”), alteration of *cratsen (“to scratch”). The root is Germanic and may be inherited from Proto-West Germanic. Ultimately from Proto-Germanic *krattōną (“to scratch”), from Proto-Indo-European *gred-, *grod- (“to scratch, scrape”); ultimately onomatopoeic in origin (compare crush, crow). From a surface analysis, maybe related to Proto-Germanic *skraudō (“scraps, shreds”); also Old English scrama (“scratch”), among other Germanic roots beginning with *skr- (cf. scrape). Compare related Old Swedish kratta (“to scratch”), Swedish kratta (“to rake”), Danish kratte (“to scratch”), Icelandic krota (“to engrave”); Old Norse *kratsa, Danish kradse (“to scratch, scrape, claw”), Swedish kratsa (“to scratch”), Icelandic krassa (“to scrawl”); Dutch kratsen (“to scratch”), Low German kratten, Old High German krazzōn, crazōn (“to scratch”), Middle Low German krassen, kratsen, German kratzen (“to scratch”), Albanian gërresë (“rasp, scraper”). According to SAOB, a related word is apparently Old Swedish kraza (“to quarrel, to fight”), which could suggest a relation to English craze, from Old Norse *krasa (“to shatter”).

Compare Old English scritta (“a hermaphrodite”), which had an earlier sense of "effeminate person, castrated man," presumably related to sċieran (“to cut”). Liberman notes that Germanic glossators, not familiar with Ovid, did not know exactly how to translate Latin hermaphroditus and instead matched it with more native words related to sexual deficiencies.

From Middle English scrat, from Old English *scrætt, from Proto-Germanic *skrattuz (“troll, forest monster”). Compare German Schratt and Old Norse skratti.