ardency vs avidity

ardency

noun
  • Intensity of feelings. 

  • Intensity of devotion. 

  • Intensity of light. 

  • Intensity of heat or burning. 

avidity

noun
  • Eagerness; intenseness of desire. 

  • Greediness; strong appetite. 

  • The measure of the synergism of the strength of individual interactions between proteins. 

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