boo-boo vs nightmare

boo-boo

verb
  • To make a mistake. 

  • To defecate. 

noun
  • Feces. 

  • A minor injury, such as a cut or a bruise. 

  • A mistake or error. 

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 boo-boo and nightmare occurred in a corpus of books? (source: Google Ngram Viewer )