nightmare vs temperament

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. 

temperament

noun
  • A tendency to become irritable or angry. 

  • Individual differences in behavior that are biologically based and are relatively independent of learning, system of values and attitudes. 

  • A person's usual manner of thinking, behaving or reacting. 

  • The altering of certain intervals from their correct values in order to improve the moving from key to key. 

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