flame-retardant vs inflammable

flame-retardant

adj
  • Hard to ignite; not supporting or conveying flame. 

noun
  • A substance used to make an object flameproof. 

inflammable

adj
  • Incapable of burning; not easily set on fire. 

  • Capable of burning; easily set on fire. 

  • Easily excited; set off by the slightest excuse; easily enraged or inflamed. 

noun
  • Any inflammable substance. 

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