delusion vs fantasy

delusion

noun
  • That which is falsely or delusively believed or propagated; false belief; error in belief. 

  • A false belief that is resistant to confrontation with actual facts. 

  • A fixed, false belief, that will not change, despite evidence to the contrary. 

  • The state of being deluded or misled, or process of deluding somebody. 

fantasy

noun
  • That which comes from one's imagination. 

  • A fantastical design. 

  • The drug gamma-hydroxybutyric acid. 

  • The literary genre generally dealing with themes of magic and the supernatural, imaginary worlds and creatures, etc. 

verb
  • To imagine; to conceive mentally. 

  • To fantasize (about). 

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