fragility (n.)youdaoicibaDictYouDict[fragility 词源字典]
late 14c., "moral weakness," from Old French fragilité "debility, frailty" (12c.), from Latin fragilitatem (nominative fragilitas) "brittleness, weakness," from fragilis "brittle, easily broken," from root of frangere "to break" (see fraction). Meaning "quality of being easily broken" is from late 15c.[fragility etymology, fragility origin, 英语词源]