Definition of inflammable in English:



  • Easily set on fire.

    ‘inflammable materials’
    • ‘It burst into flames after its highly inflammable gas ignited.’
    • ‘Bundles of goods containing inflammable materials and electricity wires dangerously hanging overhead cause recurrent fire.’
    • ‘A room in which inflammable gas and oxygen are regularly present, such as, perhaps, a chemical laboratory, is one in which every effort will be made to prevent the occurrence of electric sparks.’
    • ‘The workers were trapped on upper floors after raw and inflammable materials stored on the ground floor caught fire.’
    • ‘A thorough inspection of the complex 40-hectare site, which contains numerous highly inflammable gas and liquid gas storage and production facilities, would require weeks.’
    • ‘Bundles of goods containing inflammable material can be seen lying on foot paths blocking already narrow lanes.’
    • ‘There was other inflammable material at hand in the 1760s.’
    • ‘A spokesman said such staircases were meant to be ‘sterile’ areas without inflammable materials.’
    • ‘The inquest was told that the fire was deliberately started when inflammable liquid was poured through the couple's letterbox and ignited using a wick made out of cotton-like material.’
    • ‘Clearing the top floor of all inflammable materials, lumber etc., will lessen the danger of fire, and prevent a fire spreading.’
    • ‘I saw a lot of highly inflammable materials stacked together while 30 to 40 gas bottles were moved from the scene.’
    • ‘Residents began clapping and chanting in support of the resistance and threw straw and other inflammable materials on the fire.’
    • ‘Pure phosphorus is a non-metallic solid which exists in three forms, one of them highly poisonous and spontaneously inflammable.’
    • ‘Highly inflammable methane gas, pumped out harmlessly when mines were open, is building up in abandoned shafts and posing a potential threat to people living on the surface.’
    • ‘These have a greater capacity for overloading circuits which increases the risk of fire. You should also make sure the fuse box does not have inflammable material stored against or near it.’
    • ‘A rocket is a cylindrical metal object containing inflammable material, which, when ignited, propels the rocket to a significant height or distance.’
    • ‘If you are surrounded by easily available inflammable material, you don't have to worry about fuel economy.’
    • ‘He gave instructions accordingly, but directed that all safety precautions should be taken to prevent inflammable material falling off the wharf into the oil.’
    • ‘A water extinguisher can put out things like burning wood, paper or cardboard, but it does not work well on electrical fires or fires involving inflammable liquids.’
    • ‘Some of the worst domestic fire outbreaks have been a result of keeping inflammable liquids in homes.’
    flammable, combustible, incendiary, explosive
    unstable, volatile
    burnable, ignitable
    View synonyms


  • A substance which is easily set on fire.

    • ‘Vessels shall leave the docks immediately upon loading inflammables in the port of Montevideo.’
    • ‘The fire broke out when a passenger sprayed inflammables on the floor from two bottles and set fire to it.’
    • ‘‘As a garage, we have particular concerns such as vehicle collision, sparks igniting inflammables such as petrol or brake fluid and also manual lifting,’ he said.’
    • ‘This important conclusive finding immediately sets at rest the allegation that a mob poured inflammables from outside into the compartment and set the rail compartment ablaze.’


The words inflammable and flammable both have the same meaning, ‘easily set on fire’. This might seem surprising, given that the prefix in- normally has a negative meaning (as in indirect and insufficient), and so it might be expected that inflammable would mean the opposite of flammable, i.e. ‘not easily set on fire’. In fact, inflammable is formed using a different Latin prefix in-, which has the meaning ‘into’ and here has the effect of intensifying the meaning of the word in English. Flammable is a far commoner word than inflammable and carries less risk of confusion


Early 17th century: from French, or from Latin inflammare (see inflame).