harshen vs indurate

harshen

verb
  • To make, or to become harsh; render hard and rough. 

  • To render peevish, morose, or austere. 

indurate

verb
  • To make callous or unfeeling. 

  • To inure; to strengthen; to make hardy or robust. 

  • To harden or to grow hard. 

adj
  • Hardened, obstinate, unfeeling, callous. 

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