callous vs pachydermatous

callous

adj
  • Having calluses, or relating to calluses. 

  • Emotionally hardened; unfeeling and indifferent to the suffering/feelings of others. 

pachydermatous

adj
  • Of or relating to the pachyderms. 

  • Like an elephant 

  • Thick-skinned; insensitive. 

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