contraposition

noun

con·​tra·​po·​si·​tion ˌkän-trə-pə-ˈzi-shən 

: the relationship between two propositions when the subject and predicate of one are respectively the negation of the predicate and the negation of the subject of the other

Word History

Etymology

Late Latin contraposition-, contrapositio, from Latin contraponere to place opposite, from contra- + ponere to place — more at position

First Known Use

1551, in the meaning defined above