helpless vs unmitigable

helpless

adj
  • Uncontrollable. 

  • Unable to defend oneself. 

  • Unable to act without help; needing help; feeble. 

  • Lacking help; powerless. 

unmitigable

adj
  • Not able to be mitigated or made less severe; not mitigable. 

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