slender (adj.)youdaoicibaDictYouDict[slender 词源字典]
c. 1400, earlier sclendre (late 14c.), probably from a French source, often said to be from Old French esclendre "thin, slender," which could be from Old Dutch slinder, but the connections, and even the existence of these words, is doubtful. Related: Slenderly; slenderness.[slender etymology, slender origin, 英语词源]