irrefutably
adverb/ˌɪrɪˈfjuːtəbli/, /ɪˈrefjətəbli/
/ˌɪrɪˈfjuːtəbli/, /ɪˈrefjətəbli/
(formal)- in a way that cannot be proved wrong and that must therefore be accepted
Check pronunciation:
irrefutably