defensiveyoudaoicibaDictYouDict[defensive 词源字典]
c. 1400 (adj. and noun), from French défensif (14c.), from Medieval Latin defensivus, from defens-, past participle stem of Latin defendere (see defend). Of persons, "alert to reject criticism," from 1919. Related: Defensively; defensiveness.[defensive etymology, defensive origin, 英语词源]