bombproof vs reinforced

bombproof

adj
  • Sufficiently strong to resist the effects of a blast from a bomb. 

noun
  • An air-raid shelter, a structure designed to give protection against air raids and bombs. 

verb
  • To make resistant to bomb blasts. 

reinforced

adj
  • Having been or containing reinforcement. 

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