denounce vs grass up

denounce

verb
  • To make a formal or public accusation against; to inform against; to accuse. 

  • To claim the right of working a mine that is abandoned or insufficiently worked. 

  • To criticize or speak out against (someone or something); to point out as deserving of reprehension, etc.; to openly accuse or condemn in a threatening manner; to invoke censure upon; to stigmatize; to blame. 

  • To announce the termination of; especially a treaty or armistice. 

grass up

verb
  • To betray by informing on. 

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