durable vs infirm

durable

noun
  • A durable thing, one useful over more than one period, especially a year. 

adj
  • Able to resist wear or decay; lasting; enduring. 

infirm

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

adj
  • Weak or ill, not in good health. 

  • Irresolute; weak of mind or will. 

  • Frail; unstable; insecure. 

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