snitch vs tip off

snitch

verb
  • To inform on, especially in betrayal of others. 

  • To contact or cooperate with the police for any reason. 

noun
  • A ball used in the sport of Quidditch. 

  • A thief. 

  • An informer, one who betrays his group. 

  • A nose. 

  • A tiny morsel. 

tip off

verb
  • To alert or inform (someone), especially confidentially. 

  • To begin. 

  • To use a particular brush technique for producing a flawless surface on a wet coat of paint. 

  • To put the ball in play by throwing it up between two opponents. 

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