appetite vs avidity

appetite

noun
  • Any strong desire; an eagerness or longing. 

  • Desire to eat food or consume drink. 

  • The desire for some personal gratification, either of the body or of the mind. 

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 appetite and avidity occurred in a corpus of books? (source: Google Ngram Viewer )