rot: [OE] Rot goes back to a prehistoric Germanic *rutjan, which also produced Dutch rotten. It may be related ultimately to Latin rudis ‘rough’, source of English rude. The adjective rotten [13] was borrowed from Old Norse rotinn, which came from the same Germanic stem as produced *rutjan. The mild imprecation drat [19] is a conflation of God and rot. => rude[rot etymology, rot origin, 英语词源]