fireproof vs noncombustible

fireproof

adj

  • Resistant to damage from fire. 

verb

  • To make resistant to damage from fire. 

noncombustible

adj

  • That will not readily ignite and burn. 

noun

  • Any substance that is not combustible. 

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