contraposition (n.)youdaoicibaDictYouDict[contraposition 词源字典]
1550s, from Late Latin contrapositionem (nominative contrapositio), noun of action from past participle stem of contraponere, from contra "against" (see contra) + ponere "to put, place" (past participle positus; see position (n.)).[contraposition etymology, contraposition origin, 英语词源]