incontrovertibly vs irrefutably

incontrovertibly

adv
  • In an incontrovertible manner; in a manner not capable of being denied, challenged, or disputed. 

irrefutably

adv
  • In an irrefutable manner; beyond the possibility of refutation. 

How often have the words incontrovertibly and irrefutably occurred in a corpus of books? (source: Google Ngram Viewer )