Synonyms for Incontrovertible (same or very similar meaning)
WordNet sense 1 (impossible to deny or disprove):
irrefutable, positiveWordNet sense 2 (not possible to deny):
undeniableWordNet sense 3 (necessarily or demonstrably true):
demonstrableWordNet sense 4 (incapable of being contested or disputed):
incontestibleFrom the ODE community, based on WordNetadd/edit