nightmare vs sorrow

nightmare

noun
  • Any bad, miserable, difficult or terrifying situation or experience that arouses anxiety, terror, agony or great displeasure. 

  • A very bad or frightening dream. 

  • A feeling of extreme anxiety or suffocation experienced during sleep; Sleep paralysis. 

verb
  • To have a nightmare. 

sorrow

noun
  • unhappiness, woe 

  • (usually in plural) An instance or cause of unhappiness. 

verb
  • To feel grief over; to mourn, regret. 

  • To feel or express grief. 

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