cast iron vs crushing

cast iron

noun
  • A hard and brittle, but strong, alloy of iron, carbon, and silicon, formed by casting in a mould. 

adj
  • Inflexible or without exception. 

  • Made of cast iron. 

  • Durable; tough; resilient. 

crushing

noun
  • Crushed material. 

  • The act of subjecting sugarcane to crushing. 

  • The action of the verb to crush. 

  • A former method of execution by placing heavy weights on the victim. 

adj
  • Devastatingly disheartening. 

  • That crushes; overwhelming. 

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