coldness vs unconcern

coldness

noun
  • Limited enthusiasm or affection; coolness. 

  • The sensation resulting from exposure to low temperatures. 

  • The relative lack of heat. 

  • The reciprocal of absolute temperature. 

unconcern

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

  • Freedom from worry or apprehensiveness; insouciance or nonchalance. 

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