justyoudaoicibaDictYouDict[just 词源字典]
just: [14] Latin jūs originated in the terminology of religious cults, perhaps to begin with signifying something like ‘sacred formula’. By classical times, however, it denoted ‘right’, and particularly ‘legal right, law’, and it has provided English with a number of words connected with ‘rightness’ in general and with the process of law. The derived adjective jūstus has produced just and, by further derivation, justice [12] and justify [14].

The stem form jūr- has given injury, jury [14], objurgate [17], and perjury [14]. And combination with the element -dic- ‘say’ has produced judge, judicial, juridical, and jurisdiction. Not part of the same word family, however, is adjust [17], which comes ultimately from Vulgar Latin *adjuxtāre ‘put close to’, a compound verb based on Latin juxtā ‘close’ (whence English juxtaposition).
=> injury, judge, jury, objurgate, perjury[just etymology, just origin, 英语词源]
just (adj.)youdaoicibaDictYouDict
late 14c., "righteous in the eyes of God; upright, equitable, impartial; justifiable, reasonable," from Old French juste "just, righteous; sincere" (12c.), from Latin iustus "upright, equitable," from ius "right," especially "legal right, law," from Old Latin ious, perhaps literally "sacred formula," a word peculiar to Latin (not general Italic) that originated in the religious cults, from PIE root *yewes- "law" (cognates: Avestan yaozda- "make ritually pure;" see jurist). The more mundane Latin law-word lex covered specific laws as opposed to the body of laws. The noun meaning "righteous person or persons" is from late 14c.
just (adv.)youdaoicibaDictYouDict
"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).