indefinitely vs obdurately

indefinitely

adv
  • Forever. 

  • In a manner that is not definite. 

  • For a long time, with no defined end. 

obdurately

adv
  • In an obdurate manner; stubbornly, intractably or inflexibly. 

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