certifiably vs vastly

certifiably

adv
  • To a great extent. 

  • With the potential for certification. 

  • Undoubtedly, demonstrably. 

  • Genuinely 

vastly

adv
  • Greatly, in a vast manner. 

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