cast iron vs sturdy

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. 

sturdy

adj
  • Of firm build; stiff; stout; strong. 

  • Resolute, in a good sense; or firm, unyielding quality. 

  • Solid in structure or person. 

noun
  • A disease caused by a coenurus infestation in the brain of an animal, especially a sheep or canid; coenurosis. 

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