despair vs nightmare

despair

verb
  • To cause to despair. 

  • To be hopeless; to have no hope; to give up all hope or expectation. 

noun
  • That which causes despair. 

  • Loss of hope; utter hopelessness; complete despondency. 

  • That which is despaired of. 

nightmare

verb
  • To have a 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. 

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