nonchalant vs unruffled

nonchalant

adj
  • Casually calm and relaxed. 

  • Indifferent; unconcerned; behaving as if detached. 

unruffled

adj
  • Calm, not ruffled, serene, at peace, unbothered. 

  • Not ruffled or tousled. 

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