tart (adj.)youdaoicibaDictYouDict[tart 词源字典]
"having a sharp taste," 1520s, also attested once, obscurely, from late 14c., perhaps from Old English teart "painful, sharp, severe, rough" (in reference to punishment, pain, suffering), from Germanic *ter-t-, from PIE *der- (2) "to split, flay, peel" (see tear (v.1)), but the gap in the record is unexplained. Figurative use, with reference to words, speech, etc., is attested from c. 1600. Related: Tartly; tartness, both also absent in Middle English.[tart etymology, tart origin, 英语词源]