well-endowed (adj.)youdaoicibaDictYouDict[well-endowed 词源字典]
1680s, "with ample material endowments," from well (adv.) + past participle of endow (v.). Sexual sense is attested from 1951. A Middle English term for "naturally well-endowed" was furnished in nature.[well-endowed etymology, well-endowed origin, 英语词源]