reductio ad absurdum is a noun meaning "(reduction to the absurd) a disproof by showing that the consequences of the proposition are absurd; or a proof of a proposition by showing that its negation leads to a contradiction". It carries one recorded sense.
Definitions, synonyms and semantic relations for reductio ad absurdum come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.