frail (adj.)youdaoicibaDictYouDict[frail 词源字典]
mid-14c., "morally weak," from Old French fraile, frele "weak, frail, sickly, infirm" (12c., Modern French frêle), from Latin fragilis "easily broken" (see fragility). It is the Frenchified form of fragile. Sense of "easily destroyed, liable to break" in English is from late 14c. The U.S. slang noun meaning "a woman" is attested from 1908; perhaps with awareness of Shakespeare's "Frailty, thy name is woman."[frail etymology, frail origin, 英语词源]