ratter

From rat + -er. rat comes from Middle English raat, rat, ratt, ratte, rotte, from Old English ræt, rætt, from Proto-West Germanic ratt, from Proto-Germanic rattaz, rattō (“rat”), of uncertain origin, possibly from Proto-Indo-European Hreh₃d- (“to gnaw, scrape, scratch”). However, the rat may have been unknown in Northern Europe in antiquity, and the Proto-Germanic word may have referred to a different animal; see rattaz for more. Attestation of this family of words begins in the 12th century. 2 Cognate with frr root (“rat”), stq Rotte (“rat”), West Frisian rôt (“rat”), Dutch rat, rot (“rat”), German Ratte (“rat”), lb Rat (“rat”), wym rot, rott (“rat”), Yiddish ראַץ (“rat”), Danish and Norwegian Bokmål rotte (“rat”), Faroese and Icelandic rotta (“rat”), Norwegian Nynorsk rotta, rotte, røtte (“rat”), Swedish råtta (“rat”), Latin rattus, ratus (“rat”) (whence Asturian ratu (“mouse”), Catalan rata (“rat”), French rat (“rat”), Italian ratto (“rat”), Portuguese rato (“rat”), Spanish rata (“rat”), rato (“male rat”)); also Latin rōdō (“to bite, gnaw, nibble; to backbite, disparage, slander”), Sanskrit रदति (“to scrape, scratch; to cut path, pave; to lead river into a channel; to bestow, convey”).

Etymology from Wiktionary, CC BY-SA