nightmare vs tremble

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. 

tremble

verb
  • To fear; to be afraid. 

  • To shake, quiver, or vibrate. 

noun
  • A shake, quiver, or vibration. 

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