You searched for: “nonflammable”
flammable, inflammable, nonflammable
flammable (FLAM uh buhl) (adjective)
Pertaining to something which is capable of being set on fire and of burning quickly: Gasoline is a very flammable liquid.
inflammable (in FLAM uh buhl) (adjective)
Easily excited, aroused, or angered: "Roy had an inflammable temper when he felt he was being wronged" is a proper usage, but it should no longer be used with reference to something that will not burn.

The word inflammable actually means "able to burn"; while "nonflammable" means "unable or unlikely to burn".

The prefix "in-", used with inflammable is an intensifier not a "negative" as with such words as "inhospitable", "inhuman", "insensible", "indecent", "inadequate", etc. It has been a mistake believed by many people that inflammable meant "not flammable" and some serious injuries resulted over the years because of this misunderstanding.

As a consequence, many English-speaking countries passed laws that have required manufacturers of materials and substances that burn easily to use the word "flammable" in place of inflammable, which is considered less ambiguous or confusing.

So remember that inflammable comes from "inflame", which, in this case, means "to set on fire" and not from "in-", "not" + "flammable", "combustible".

nonflammable (nahn FLAM uh buhl) (adjective)
Descriptive of something that is not readily ignited and so it does not burn easily: It is much more realistic that people use nonflammable or "non-flammable" instead of inflammable when they mean that something cannot burn or is very difficult to burn.

In the confusion at the store, which was caused by a customer's inflammable temper, Joseph was unable to read the sign to see if the can of solvent was flammable or nonflammable.

This entry is located in the following units: -able (page 15) Confusing Words Clarified: Group F; Homonyms, Homophones, Homographs, Synonyms, Polysemes, etc. + (page 4)
nonflammable (adjective) (not comparable)
1. Pertaining to something difficult to burn or to ignite: It seemed that the moist sticks were nonflammable because they certainly were hard to kindle.
2. Concerning something that is not combustible or easily set on fire: The matches were very old and had been stored in the basement so they were nonflammable when Jane wanted to light the candle, so she got new ones from the store the next day.
This entry is located in the following units: -able (page 27) flam- (page 2) non- + (page 4)