cast iron vs daring

cast iron

adj
  • Durable; tough; resilient. 

  • Inflexible or without exception. 

  • Made of cast iron. 

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

daring

adj
  • Courageous or showing bravery; doughty. 

  • Racy; sexually provocative. 

  • Adventurous, willing to take on or look for risks; overbold. 

noun
  • Boldness. 

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