languor vs unconcern

languor

noun
  • Listless indolence or inactivity, especially if enjoyable or relaxing; dreaminess; (countable) an instance of this. 

  • A state of the body or mind caused by exhaustion or disease and characterized by a languid or weary feeling; lassitude; (countable) an instance of this. 

  • Dullness, sluggishness; lack of vigour; stagnation. 

  • Heavy humidity and stillness of the air. 

  • Melancholy caused by lovesickness, sadness, etc.; (countable) an instance of this. 

verb
  • To languish. 

unconcern

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

  • Freedom from worry or apprehensiveness; insouciance or nonchalance. 

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