just (adv.)youdaoicibaDictYouDict[just 词源字典]
"merely, barely," 1660s, from Middle English sense of "exactly, precisely, punctually" (c. 1400), from just (adj.), and paralleling the adverbial use of French juste. Just-so story first attested 1902 in Kipling, from the expression just so "exactly that, in that very way" (1751).[just etymology, just origin, 英语词源]