trenchant (adj.)youdaoicibaDictYouDict[trenchant 词源字典]
early 14c., "cutting, sharp," from Old French trenchant "cutting, sharp" (literal and figurative), present participle of trenchier "to cut" (see trench). Figurative sense in English is from c. 1600.[trenchant etymology, trenchant origin, 英语词源]