keenness vs zeal

keenness

noun
  • eagerness or enthusiasm 

  • sharpness or cutting ability 

  • astuteness or sagacity 

zeal

noun
  • The fervour or tireless devotion for a person, cause, or ideal and determination in its furtherance; diligent enthusiasm; powerful interest. 

  • The collective noun for a group of zebras. 

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