palm off vs sneak in

palm off

verb
  • To sell or dispose of (something) with the intent to deceive; to attempt to pass off a counterfeit or inferior product as genuine. 

sneak in

verb
  • To take (something) in covertly, to smuggle. 

  • To enter without being noticed. 

  • To barely advance or be allowed entry in a competition or organization despite minimal credentials or competitors thought to be superior. 

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