nightmare vs sicken

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. 

sicken

verb
  • To make ill. 

  • To fill with disgust or abhorrence. 

  • To become ill. 

  • To lower the standing of. 

  • To be filled with disgust or abhorrence. 

  • To become disgusting or tedious. 

  • To become weak; to decay; to languish. 

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