- not permeable; impassable.
- Chemistry, Geology. (of porous substances, rocks, etc.) not permitting the passage of a fluid through the pores, interstices, etc.
Origin of impermeable
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for impermeability
It is only when in combination that it exhibits this impermeability to the obscure rays.The Glaciers of the Alps
The impermeability of plastic clay to water is a characteristic which is important for many purposes.
The fused portion fills the pores or interstices of the material, making—when cold—a ware of great strength and impermeability.
The integrity and impermeability of this asphalt coat are quite as vital as constant saturation.
- (of a substance) not allowing the passage of a fluid through interstices; not permeable
Word Origin and History for impermeability
Online Etymology Dictionary, © 2010 Douglas Harper
- Impossible to permeate; not permitting passage.
- 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.