knock on wood vs pretend

knock on wood

verb
  • To take a customary action to ward off some misfortune that is believed to be attracted by a presumptuous statement. 

intj
  • Hopefully; a self-directive to undertake the customary action to ward off bad luck. 

pretend

verb
  • To claim, to allege, especially when falsely or as a form of deliberate deception. 

  • To feign, affect (a state, quality, etc.). 

  • To lay claim to (an ability, status, advantage, etc.). (originally used without to) 

  • To make oneself appear to do or be doing something; to engage in make-believe. 

adj
  • Not really what it is represented as being; imaginary, feigned. 

noun
  • the act of engaging in pretend play. 

How often have the words knock on wood and pretend occurred in a corpus of books? (source: Google Ngram Viewer )