nonchalance vs unease

nonchalance

noun
  • Indifference, unconcern; carelessness; coolness; disregard, detachment. 

unease

noun
  • Trouble; misery; a feeling of disquiet or concern. 

verb
  • To make uneasy or uncomfortable 

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