impaired vs infirm

impaired

adj
  • Rendered less effective. 

  • inebriated, drunk. 

noun
  • A criminal charge for driving a vehicle while impaired. 

infirm

adj
  • Irresolute; weak of mind or will. 

  • Weak or ill, not in good health. 

  • Frail; unstable; insecure. 

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

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