callous vs cold-blooded

callous

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

  • Having calluses, or relating to calluses. 

cold-blooded

adj
  • Lacking emotion or compunction. 

  • Of a type of horse: tall and muscular, usually good-natured and suitable for heavy work. 

  • Having an unregulated body temperature; ectothermic. 

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