flammable
Americanadjective
adjective
Usage
Flammable and inflammable are interchangeable when used of the properties of materials. Flammable is, however, often preferred for warning labels as there is less likelihood of misunderstanding ( inflammable being sometimes taken to mean not flammable ). Inflammable is preferred in figurative contexts: this could prove to be an inflammable situation
Commonly Confused
See inflammable.
Other Word Forms
- flammability noun
Etymology
Origin of flammable
First recorded in 1805–15; from Latin flammā(re) “to set on fire” + -ble
Explanation
Be careful with matches around gasoline, dry grass, and old wood because they are all very flammable and might catch on fire. Flammable is a pretty straightforward word with one odd fact about it. The word, inflammable, which sounds like the opposite of flammable, actually means the same thing — easily catching on fire. If you want to say that something won't catch fire easily, use fireproof and you'll be sure to be right.
Vocabulary lists containing flammable
Power Suffix: -able
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List 6
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Hatchet
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Hydrogen, a highly flammable gas that produces heat and water when it burns, can be used to refine petroleum and make chemicals, metals and fertilisers.
From BBC • Mar. 11, 2026
Hydrogen is leakier and more flammable, and it burns hotter and faster than gas.
From Los Angeles Times • Feb. 16, 2026
The warehouse and surrounding storage areas were filled with stacks of pallets and cardboard boxes containing highly flammable ethanol-based hand sanitizer, according to court documents.
From Los Angeles Times • Feb. 7, 2026
In 2015, blasts at warehouses containing flammable chemicals in the port city of Tianjin killed more than 170 people and injured 700 others.
From Barron's • Jan. 18, 2026
“A candle. You want to light a candle in here? In a room filled with very dry, flammable things?”
From "Night Owls" by A.R. Vishny
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
