fervor vs zest

fervor

noun
  • An intense, heated emotion; passion, ardor. 

  • Heat. 

  • A passionate enthusiasm for some cause. 

zest

noun
  • Enthusiasm; keen enjoyment; relish; gusto. 

  • The outer skin of a citrus fruit, used as a flavouring or garnish. 

  • General vibrance of flavour. 

  • The woody, thick skin enclosing the kernel of a walnut. 

verb
  • To scrape the zest from a fruit. 

  • To make more zesty. 

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