coolness vs insouciance

coolness

noun

  • Indifference; lack of passion or interest. 

  • The state of being cool, i.e. calm. 

  • The state of being cool, i.e. good or pleasing. 

  • The result or product of being cool, i.e. good or pleasing. 

  • The state of being cool, i.e. chilly. 

  • The result or product of being cool, i.e. chilly. 

insouciance

noun

  • Carelessness, heedlessness, indifference, or casual unconcern. 

  • Nonchalance. 

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