nonchalant vs phlegmatic

nonchalant

adj
  • Indifferent; unconcerned; behaving as if detached. 

  • Casually calm and relaxed. 

phlegmatic

adj
  • Not easily excited to action or passion; calm; sluggish. 

  • Generating, causing, or full of phlegm. 

noun
  • One who has a phlegmatic disposition. 

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