contrapositive.

A reformulation of an if-then statement that swaps its two parts and negates both.

Use it for

Words that belong together

• the contrapositive of a statement
• prove the contrapositive

On the page

The contrapositive of 'If it is a square, it has four sides' is 'If it does not have four sides, it is not a square.'

Usage notes

Primary category: analysis / argumentation / evidence. Forms: noun singular contrapositive; plural contrapositives. Adjective use normally non-gradable. Writing functions: inference, proof, qualification. Commonness: uncommon outside logic study. No forced synonym or antonym.