mordacious (adj.)youdaoicibaDictYouDict[mordacious 词源字典]
"given to biting," 1640s (originally figurative), from Latin mordac-, stem of mordax, from mordere "to bite," perhaps from PIE root mer- (2) "to rub, harm" (see smart (v.)). Related: Mordacity.[mordacious etymology, mordacious origin, 英语词源]