afraid vs cautious

afraid

adj
  • Impressed with fear or apprehension; in fear. 

  • Regretful, sorry; expressing a reluctance to face an unpleasant situation. 

  • Worried about, feeling concern for, fearing for (someone or something). 

cautious

adj
  • Using or exercising caution; careful; tentative 

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