Definition of impermeable in English:



  • Not allowing fluid to pass through.

    ‘an impermeable membrane’
    • ‘The material must be continuous and virtually impermeable to air.’
    • ‘Because this layer should permit passage of fluid, impermeable dressings are not recommended.’
    • ‘Also, old clay pots can build up enough fertilizer and salts to make them impermeable to air and water.’
    • ‘It creates a flexible seal that is completely impermeable to water, dust, insects, rodents and vibration.’
    • ‘Do health care workers really need a single fabric that is 100% impermeable to bloodborne viruses and bacteria to be used in every surgical procedure?’
    • ‘This will render the topo impermeable, yet still allow you to write notes on it with a ballpoint pen.’
    • ‘Some have succeeded in making their cell walls impermeable to antibiotics.’
    • ‘The authors conclude that applying a mattress cover that is impermeable to house-dust mite allergen on the beds of children and their parents reduces night cough in the second year of life.’
    • ‘Local media have questioned some projects, such as draining water from the chain of lakes outside the Old Summer Palace ruins to install an impermeable membrane that would stop water from seeping into the ground.’
    • ‘I had noticed that gumboots were impermeable to water from the outside, and deduced that they must also be impermeable from the inside.’
    • ‘Lacquer, the sap of a tree, has to be applied in thin layers over a long period to build up a surface that is impermeable to liquids.’
    • ‘The gasket has a core that is impermeable to liquids, with a first side and a second side opposite the first side.’
    • ‘This may involve professional help, as your roof has to be strong enough to support the mat of plants, and it will also require an impermeable membrane underneath.’
    • ‘Condoms are essentially impermeable to particles the size of STD pathogens including the smallest sexually transmitted virus.’
    • ‘The plastic is hydrophobic and thus impermeable to ions and water.’
    • ‘However, the inside lining of the heart is smooth and impermeable to the oxygen tied to the red cells.’
    • ‘But even watertight concrete is not impermeable to the passage of moisture.’
    • ‘The resulting concrete is said to be impermeable to the migration of water or waterborne chemicals.’
    • ‘The sea snake's skin is impermeable to water but they can extract 20% of their oxygen needs through their skin from oxygen dissolved in seawater.’
    • ‘He developed a mattress cover which is free of the suspected chemicals and impermeable to gasses.’
    watertight, waterproof, damp-proof, water-resistant, water-repellent, airtight, tight, sealed, hermetically sealed, closed
    impenetrable, impregnable, inviolable, resistant
    View synonyms


Late 17th century: from French imperméable, or from late Latin impermeabilis, from in- not + permeabilis (see permeable).