heat of passion vs rancor

heat of passion

noun
  • An outburst of anger that leads one to commit a criminal act, and is itself influenced by preceding events that might cause a reasonable person to lose self control. 

rancor

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

  • Rancidity, rankness. 

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