backhandedness vs sardonicism

backhandedness

noun
  • Deceit or neglect. 

  • Insincerity, irony, or sarcasm. 

  • Indirection. 

  • Backwardness of direction. 

  • The use of a backward flip of the hand. 

  • Leftward slant. 

sardonicism

noun
  • The quality of being sardonic 

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