dullness vs languor

dullness

noun
  • The quality of being uninteresting; boring; humorless or irksome. 

  • The quality of not perceiving or kenning things distinctly. 

  • The quality of being slow of understanding things; stupidity. 

  • Lack of interest or excitement. 

  • The lack of visual brilliance; want of sheen. 

  • bluntness. 

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. 

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