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.
not permeable; not permitting fluids to pass through it; impenetrable
Origin of impermeableLate Latin impermeabilis
Impossible to permeate: an impermeable membrane; an impermeable border.
- im·per′me·a·bil′i·ty, im·per′me·a·ble·ness
(comparative more impermeable, superlative most impermeable)