refuse vs undertake

refuse

adj
  • Discarded, rejected. 

verb
  • To decline a request or demand, forbear; to withhold permission. 

  • To melt again. 

  • To decline (a request or demand). 

  • To throw back, or cause to keep back (as the centre, a wing, or a flank), out of the regular alignment when troops are about to engage the enemy. 

noun
  • Collectively, items or material that have been discarded; rubbish, garbage. 

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 refuse and undertake occurred in a corpus of books? (source: Google Ngram Viewer )