helpless vs incapable

helpless

adj
  • Lacking help; powerless. 

  • Unable to defend oneself. 

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

  • Uncontrollable. 

incapable

adj
  • Not capable (of doing something); unable. 

  • Not in a state to receive; not receptive; not susceptible; not able to admit. 

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