hell-bent vs tireless

hell-bent

adj
  • Recklessly determined to do or achieve (something). 

adv
  • In a recklessly determined manner; determinedly, wholeheartedly. 

tireless

adj
  • Indefatigable, untiring and not yielding to fatigue 

  • Without a tire (wheel covering); tyreless. 

How often have the words hell-bent and tireless occurred in a corpus of books? (source: Google Ngram Viewer )