pretend vs undertake

pretend

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

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

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

  • 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. 

undertake

verb
  • To commit oneself (to an obligation, activity etc.). 

  • To pass a slower moving vehicle on the curbside rather than on the side closest to oncoming traffic. 

  • To take upon oneself; to start, to embark on (a specific task etc.). 

noun
  • The passing of slower traffic on the curbside rather than on the side closest to oncoming traffic. 

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