reticence (n.)youdaoicibaDictYouDict[reticence 词源字典]
c. 1600, from Middle French réticence (16c.), from Latin reticentia "silence, a keeping silent," from present participle stem of reticere "keep silent," from re- (see re-), + tacere "be silent" (see tacit). "Not in common use until after 1830" [OED].[reticence etymology, reticence origin, 英语词源]