cautionary vs prophylactic

cautionary

adj

  • Serving to ward off; preventive 

  • Serving to caution or warn; admonitory 

prophylactic

adj

  • Serving to prevent or protect against an undesired effect, especially disease or pregnancy 

noun

  • A medicine which preserves or defends against disease; a preventive. 

  • Any device or mechanism intended to prevent harmful consequences. 

  • A prophylactic condom. 

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