adjective 1.not
passable; not allowing passage over, through, along, etc.:
Heavy snow made the roads impassable. 2.unable to be surmounted: an impassable obstacle to further negotiations.
3.(of currency) unable to be circulated: He tore the bill in half, making it impassable.
Related forms im·pass·a·bil·i·ty, im·pass·a·ble·ness, noun
im·pass·a·bly, adverb