cautious vs guarded

cautious

adj
  • Using or exercising caution; careful; tentative 

guarded

adj
  • Cautious; restrained. 

  • Watched over; supervised. 

  • When the practitioner formulating the opinion does not have enough information to know, or to foretell, what the outcome may be. 

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