risibly vs unbelievably

risibly

adv
  • In a risible manner. 

unbelievably

adv
  • Contrary to expectations, amazingly. 

  • To an extent not to be believed. 

  • In a manner that one does not or cannot believe. 

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