Wiktionary
incontestible
a. (alternative spelling of incontestable English)
WordNet
incontestible
adj. incapable of being contested or disputed [syn: incontestable] [ant: contestable]
Usage examples of "incontestible".
My theory is that Dory said she had incontestible proof about her father.
And there was the final and incontestible proof that these people weren't the lunatics Klein had marked them as, for they saw the humour in it too.