forgo vs undertake

forgo

verb
  • To do without, to abandon, to renounce. 

  • To let pass, to leave alone, to let go. 

  • To refrain from, to abstain from, to pass up, to withgo. 

undertake

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

  • 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. 

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

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