Antonyms of adj navigable

1 sense of navigable

Sense 1
navigable -- (able to be sailed on or through safely; "navigable waters"; "a navigable channel")

INDIRECT (VIA passable) -> impassable, unpassable -- (incapable of being passed)

Similarity of adj navigable

1 sense of navigable

Sense 1
navigable -- (able to be sailed on or through safely; "navigable waters"; "a navigable channel")
       => passable (vs. impassable) -- (able to be passed or traversed or crossed; "the road is passable")