futility vs inanity

futility

noun
  • The quality of being futile or useless. 

  • Something, especially an act, that is futile. 

  • Unimportance. 

inanity

noun
  • The property of being inane, of lacking material of interest or satisfaction, emptiness. 

  • Something that is inane. 

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