build castles in the air vs feign

build castles in the air

verb
  • To have any desire, idea, or plan that is unlikely to be realized; to imagine visionary projects or schemes; to have an idle fancy or a pipe dream; to daydream. 

feign

verb
  • To imagine; to invent; to pretend to do something. 

  • To hide or conceal. 

  • To make an action as if doing one thing, but actually doing another, for example to trick an opponent; to feint. 

  • To make a false show or pretence of; to counterfeit or simulate. 

How often have the words build castles in the air and feign occurred in a corpus of books? (source: Google Ngram Viewer )