Definition of ad absurdum in US English:

ad absurdum

(also ad absurdem)


  • To the point of absurdity; so as to demonstrate that the consequence of making a particular assumption is something absurd or contradictory; (also more generally) to an absurd or extreme degree.


  • Designating a method of demonstrating the falsity of a hypothesis by showing that the consequence of assuming it to be true is something absurd or contradictory; relating to or characteristic of such a hypothesis or demonstration.


Mid 17th century; earliest use found in John Evelyn (1620–1706), diarist and writer. From classical Latin ad to + absurdum, use as noun of neuter of absurdus, in various post-classical Latin renderings of ancient Greek ἡ εἰς ἄτοπον ἀπαγωγή reduction to the absurd (Euclid).