English Café: Flammable–Nonflammable & Combustible–Noncombustible

Advanced Details: Flammable–nonflammable & combustible–noncombustile

Best practice: Don’t use the word inflammable.

To avoid confusion, choose the adjective flammable when you are referring to something that catches fire and burns easily. And, use the relatively recent adjective nonflammable when referring to something that doesn’t catch fire and burn easily.

For advanced learners, please note that you can also replace flammable with the term combustible. The opposite of the term combustible is noncombustible.

Finally, avoid using inflammable completely.