nubilous vs sullen

nubilous

adj

  • Cloudy, misty. 

  • Unclear. 

sullen

adj

  • Gloomy; dismal; foreboding. 

  • Having a brooding ill temper; sulky. 

  • Sluggish; slow. 

noun

  • Sullen feelings or manners; sulks; moroseness. 

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