chicken out vs waive

chicken out

verb
  • To shy away from a daring task; to decline, refuse, or avoid something due to fear or uncertainty. 

waive

verb
  • To relinquish (a right etc.); to give up claim to; to forgo. 

  • To relinquish claim on a payment or fee which would otherwise be due. 

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