What does inflammable mean?
Inflammable is an adjective meaning liable to catch fire easily or readily ignited. In Britain it is standard vocabulary, especially in safety notices and descriptions of chemicals, fuels, fabrics, and other materials; in the United States, “flammable” is much more common in everyday use, although “inflammable” remains familiar in older, legal, and technical writing. The word describes a material’s capacity to ignite, not the fact that it is already burning. Its older figurative meaning is easily excited or roused to anger, but that use now sounds literary or dated. Inflammable is therefore useful for recognizing British and technical English, especially in phrases such as “highly inflammable materials,” while “flammable” is usually the clearest choice for a broad modern audience.
adjectiveLiable to catch fire easily; easily ignited or flammable.
- Easily set on fire or ignited.
- Easily roused to anger or excitement, now chiefly dated and figurative.
"The factory took special precautions with highly inflammable cleaning fluids."
"Workers must keep inflammable materials away from all sources of ignition."
"The critic dismissed the proposal as an inflammable issue likely to provoke heated debate."
Inflammable does not mean “not flammable”: it means flammable, and its roots point straight to flame.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does inflammable come from?
English “inflammable” appeared in the early 17th century and was borrowed from French. Its ultimate source is the Latin inflammare, meaning “to set on fire,” formed from the prefix in- and flamma, meaning “flame.” Related English words such as “inflamed,” “inflammation,” and “inflammatory” developed from the same Latin verbal root.
Related word forms
How inflammable is actually used
The literal adjective is standard in British English and in safety, legal, and industrial contexts. Its figurative sense is now dated, while “flammable” is usually the least marked choice for international and general audiences.
Easily confused with inflammable
The two words have the same meaning: “flammable” is the usual term in general US English, whereas “inflammable” is standard in British English and remains common in some technical contexts.
“Inflammable” describes something that can catch fire, while “inflammatory” describes something that arouses strong disagreement or provokes anger.