nightmare vs shudder

nightmare

noun
  • A very bad or frightening dream. 

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

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

verb
  • To have a nightmare. 

shudder

noun
  • A moment of almost pleasurable fear; a frisson. 

  • A shivering tremor, often from fear or horror. 

verb
  • To vibrate jerkily. 

  • To shake nervously, often from fear or horror. 

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