nonchalant vs unmannered

nonchalant

adj
  • Indifferent; unconcerned; behaving as if detached. 

  • Casually calm and relaxed. 

unmannered

adj
  • Having poor manners or social skills; ill-mannered; rude. 

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