anxiety vs insouciance

anxiety

noun
  • An uneasy or distressing desire (for something). 

  • An unpleasant state of mental uneasiness, nervousness, apprehension and obsession or concern about some uncertain event. 

  • A state of restlessness and agitation, often accompanied by a distressing sense of oppression or tightness in the stomach. 

insouciance

noun
  • Carelessness, heedlessness, indifference, or casual unconcern. 

  • Nonchalance. 

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