rancor vs viciousness

rancor

noun
  • A feeling of long-lasting ire for another, sometimes to the point of hatred, over a perceived wrongdoing; bitterness. 

  • Rancidity, rankness. 

viciousness

noun
  • the desire to cause harm to others; extreme cruelty 

  • the characteristic of being vicious 

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