frailty vs incapacity

frailty

noun
  • The condition quality of being frail, physically, mentally, or morally; weakness of resolution; liability to be deceived. 

  • A fault proceeding from weakness; foible; sin of infirmity. 

incapacity

noun
  • The lack of a capacity; an inability. 

  • Legal disqualification. 

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