fervor vs pessimism

fervor

noun
  • Heat. 

  • An intense, heated emotion; passion, ardor. 

  • A passionate enthusiasm for some cause. 

pessimism

noun
  • A general belief that bad things will happen. 

  • The condition of being pessimal. 

  • The doctrine that this world is the worst of all possible worlds. 

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