cold-blooded vs stonyhearted

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. 

stonyhearted

adj
  • Cruel, compassionless, discompassionate, as if having a heart made of stone. 

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