nightmare vs scarecrow

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. 

scarecrow

verb
  • To frighten or terrify (someone or something), as if using a scarecrow. 

  • To cause (a person, their body, etc.) to look awkward and stiff, like a scarecrow (noun sense 1). 

  • To splay (one's arms) away from the body, like the arms of a scarecrow. 

noun
  • Anything that appears terrifying but presents no danger; a paper tiger. 

  • Military equipment or tactics used to scare and deter rather than cause actual damage. 

  • A person regarded as resembling a scarecrow (sense 1) in some way; especially, a tall, thin, awkward person; or a person wearing ragged and tattered clothes. 

  • An effigy, typically made of straw and dressed in old clothes, fixed to a pole in a field to deter birds from eating crops or seeds planted there. 

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