frigidity vs sternness

frigidity

noun
  • Coldness of feeling, manner or quality; lack of ardor, animation or vivacity. 

  • The state of being frigid; coldness; lack of heat. 

  • Lack of natural heat and vigor of body; impotency. 

sternness

noun
  • The state or quality of being stern. 

  • The result or product of being stern. 

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