helplessness vs inability

helplessness

noun
  • The state of being helpless. 

  • A feeling of inadequacy or impotence. 

inability

noun
  • Lack of the option to do something; powerlessness. 

  • Lack of the ability to do something; incapability. 

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