sterility vs tarnish

sterility

noun
  • The state or quality of being sterile. 

tarnish

noun
  • Oxidation or discoloration, especially of a decorative metal exposed to air. 

verb
  • To compromise, damage, soil, or sully. 

  • To lose its lustre or attraction; to become dull. 

  • To oxidize or discolor due to oxidation. 

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