stonehearted vs unresponsive

stonehearted

adj

  • Hardhearted; pitiless; unfeeling. 

unresponsive

adj

  • Indifferent or apathetic; emotionless. 

  • Not responsive; unreactive. 

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