contraposition

UK: /ˌkɒntrəpəˈzɪʃən/ US: (kon′trə pə zish′ən)

WordReference Random House Unabridged Dictionary of American English © 2026

con•tra•po•si•tion  (kon′trə pə zish′ən), n. 

1. placement opposite or against.
2. opposition, contrast, or antithesis.
3. Philosophy [Logic.] the inference drawn from a proposition by negating its terms and changing their order, as by inferring "Not B implies not A'' from "A implies B.''

• Late Latin contrāposition- (stem of contrāpositiō). See contra-¹, position
• 1545–55

Collins Concise English Dictionary © HarperCollins Publishers::

contraposition / ˌkɒntrəpəˈzɪʃən/ noun

1. the act of placing opposite or against, esp in contrast or antithesis
2. the derivation of the contrapositive of a given categorial proposition