bolo vs cast iron

bolo

noun
  • A long, heavy, single-edged machete. 

  • A soldier not capable of the minimum standards of marksmanship. 

  • A request for law enforcement officers to be on the lookout for a suspect. 

  • a type of punch; an uppercut. 

  • A string or leather necktie secured with an ornamental slide. 

verb
  • To attack or despatch with a bolo knife. 

  • To fail to meet the minimum standards of marksmanship. 

  • To dress (somebody) in a bolo. 

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. 

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