backwater (n.)youdaoicibaDictYouDict[backwater 词源字典]
late 14c., "water behind a dam," from back (adj.) + water (n.1). Hence flat water without a current near a flowing river, as in a mill race (1820); figurative use of this for any flat, dull place is from 1899.[backwater etymology, backwater origin, 英语词源]