ardor vs strength

ardor

noun
  • Great warmth of feeling; fervor; passion. 

  • Intense heat. 

  • Spirit; enthusiasm; passion. 

strength

noun
  • The quality or degree of being strong. 

  • The intensity of a force or power; potency. 

  • The strongest part of something; that on which confidence or reliance is based. 

  • A positive attribute. 

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