Jew (n.)youdaoicibaDictYouDict[Jew 词源字典]
late 12c. (in plural, giwis), from Anglo-French iuw, Old French giu, from Latin Iudaeum (nominative Iudaeus), from Greek Ioudaios, from Aramaic jehudhai (Hebrew y'hudi) "Jew," from Y'hudah "Judah," literally "celebrated," name of Jacob's fourth son and of the tribe descended from him. Replaced Old English Iudeas "the Jews." Originally, "Hebrew of the kingdom of Judah."

Jews' harp "simple mouth harp" is from 1580s, earlier Jews' trump (1540s); the connection with Jewishness is obscure. Jew-baiting first recorded 1853, in reference to German Judenhetze. In uneducated times, inexplicable ancient artifacts were credited to Jews, based on the biblical chronology of history: such as Jews' money (1570s) "Roman coins found in England." In Greece, after Christianity had erased the memory of classical glory, ruins of pagan temples were called "Jews' castles," and in Cornwall, Jews' houses was the name for the remains of ancient tin-smelting works.[Jew etymology, Jew origin, 英语词源]
true (adj.)youdaoicibaDictYouDict
Old English triewe (West Saxon), treowe (Mercian) "faithful, trustworthy, honest, steady in adhering to promises, friends, etc.," from Proto-Germanic *treuwaz- "having or characterized by good faith" (cognates: Old Frisian triuwi, Dutch getrouw, Old High German gatriuwu, German treu, Old Norse tryggr, Danish tryg, Gothic triggws "faithful, trusty"), from PIE *drew-o-, a suffixed form of the root *deru-/*dreu- "be firm, solid, steadfast" (cognates: Lithuanian drutas "firm," Welsh drud, Old Irish dron "strong," Welsh derw "true," Old Irish derb "sure"), with specialized sense "wood, tree" and derivatives referring to objects made of wood (see tree (n.)).

Sense of "consistent with fact" first recorded c. 1200; that of "real, genuine, not counterfeit" is from late 14c.; that of "conformable to a certain standard" (as true north) is from c. 1550. Of artifacts, "accurately fitted or shaped" it is recorded from late 15c. True-love (n.) is Old English treowlufu. True-born (adj.) first attested 1590s. True-false (adj.) as a type of test question is recorded from 1923. To come true (of dreams, etc.) is from 1819.