infirm vs unwell

infirm

adj
  • Weak or ill, not in good health. 

  • Irresolute; weak of mind or will. 

  • Frail; unstable; insecure. 

verb
  • To contradict, to provide proof that something is not. 

unwell

adj
  • Not in good health; not feeling well; somewhat ill 

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