absurdity vs insanity

absurdity

noun
  • That which is absurd; an absurd action; a logical contradiction. 

  • The quality of being absurd or inconsistent with obvious truth, reason, or sound judgment. 

insanity

noun
  • The state of being insane; madness. 

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