fervor vs sluggishness

fervor

noun
  • Heat. 

  • An intense, heated emotion; passion, ardor. 

  • A passionate enthusiasm for some cause. 

sluggishness

noun
  • The state of economic decline, inactivity, slow or subnormal growth. 

  • The property of being sluggish, unable or unwilling to act quickly. 

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