fire-retardant vs fireproof

fire-retardant

adj

  • Hard to ignite; not flammable. 

noun

  • A substance that makes an object resistant to burning. 

fireproof

adj

  • Resistant to damage from fire. 

verb

  • To make resistant to damage from fire. 

How often have the words fire-retardant and fireproof occurred in a corpus of books? (source: Google Ngram Viewer )