feign vs mock up

feign

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

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

mock up

verb
  • To create a model or demonstration; to create a preliminary version or sample. 

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