certifiably vs extensively

certifiably

adv

  • To a great extent. 

  • With the potential for certification. 

  • Undoubtedly, demonstrably. 

  • Genuinely 

extensively

adv

  • To a great extent. 

  • In an extensive manner, widely. 

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