The definition of impermeable is not able to be broken through, or not allowing fluids to pass through.
An example of something impermeable is a zip-closure plastic bag.
Impossible to permeate.
An impermeable membrane; an impermeable border.
Not permeable; not permitting fluids to pass through it; impenetrable.
Relating to a material through which substances, such as liquids or gases, cannot pass. Some substances, such as some types of contact lenses, are permeable to gas but impermeable to liquid.
Origin of impermeable
From Frenchimperméable, from Latinimpermeābilis, from im- + permeābilis (“permeable”).
These are special organs which Lent~eIs interrupt the continuity of the impermeable layer of ordinary cork-cells.
The surface of the earth is rarely impermeable, and the structure of the rocks largely determines the direction of flow of so much of the rainfall as sinks into the ground and is not evaporated.
There are cases also where sedimentary rocks, formed below the sea or salt lagoons, are almost impermeable: thus the salt deposited in parts of the Upper Keuper of the New Red Sandstone, is protected by the red marls of the formation, and has never been washed out.
Thus in the western mountain districts of Great Britain, largely composed of nearly impermeable rocks more Lion.
But these protective layers are in the main impermeable by gases and by either liquid or vapour, and prevent the access of either to the protoplasts which need them.