cautioning vs suggestion

cautioning

noun
  • The act of giving a warning. 

suggestion

noun
  • The act of suggesting. 

  • Information, insinuation, speculation, as opposed to a sworn testimony and evidence. 

  • Something suggested (with subsequent adposition being for) 

  • Something implied, which the mind is liable to take as fact. 

  • The act of exercising control over a hypnotised subject by communicating some belief or impulse by means of words or gestures; the idea so suggested. 

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