guff vs thank-you note

guff

noun
  • A fart; act of breaking wind. 

  • Nonsensical talk or thinking. 

  • Superfluous information. 

  • Insolent or otherwise unacceptable remarks. 

verb
  • To mislead. 

  • To fart. 

thank-you note

How often have the words guff and thank-you note occurred in a corpus of books? (source: Google Ngram Viewer )