[in-kuh m-buhs-tuh-buh l]


not combustible; incapable of being burned; fireproof.


an incombustible substance.

Origin of incombustible

First recorded in 1425–75; late Middle English word from Medieval Latin word incombustibilis. See in-3, combustible
Related formsin·com·bus·ti·bil·i·ty, in·com·bus·ti·ble·ness, nounin·com·bus·ti·bly, adverb Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for incombustible

concrete, asbestos, fire-resistant, noncombustible, nonflammable

Examples from the Web for incombustible

Historical Examples of incombustible

  • Carbon dioxide is incombustible, since it is, like water, a product of combustion.

  • It is a transparent gas, which is incombustible and extinguishes flame.

  • I think I may say I am old and incombustible enough to be trusted.

    The Guardian Angel

    Oliver Wendell Holmes, Sr.

  • The fuse wire is usually enclosed in an incombustible holder.


    Willis Eugene Tower

  • It was burned in incombustible flax, with the orange-tree on which it used to perch.

    Voltaire's Romances

    Franois-Marie Arouet

British Dictionary definitions for incombustible



not capable of being burnt; fireproof


an incombustible object or material
Derived Formsincombustibility or incombustibleness, nounincombustibly, adverb
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for incombustible

late 15c., from Old French incombustible (14c.) or directly from Medieval Latin incombustibilis; see in- (1) + combustible.

Online Etymology Dictionary, © 2010 Douglas Harper