case-hardened vs hard-boiled

case-hardened

adj
  • Hardened by experience. 

hard-boiled

adj
  • Written in a laconic, dispassionate, often ironic style for a realistic, unsentimental effect. 

  • Cooked to a solid consistency. 

  • Callous and unsentimental. 

How often have the words case-hardened and hard-boiled occurred in a corpus of books? (source: Google Ngram Viewer )