callous vs unbending

callous

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

  • Having calluses, or relating to calluses. 

unbending

adj
  • very reserved, aloof and asocial 

  • inflexible and not yielding 

noun
  • The act of one who unbends. 

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