rancor vs ressentiment

rancor

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

  • Rancidity, rankness. 

ressentiment

noun
  • A sense of resentment arising from suppressed feelings of envy and hatred, often leading to a frustrated sense of inferiority, with various social repercussions. 

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