boredom vs unconcern

boredom

noun
  • An instance or period of being bored; A bored state. 

  • The state of being bored. 

unconcern

noun
  • Lack of interest or care; indifference or apathy. 

  • Freedom from worry or apprehensiveness; insouciance or nonchalance. 

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