Antonyms of adj surmountable

2 senses of surmountable

Sense 1
surmountable (vs. insurmountable) -- (capable of being surmounted or overcome; "situations of measurable and surmountable danger")

insurmountable (vs. surmountable), unsurmountable -- (not capable of being surmounted or overcome; "insurmountable disadvantages")
        => insuperable, unconquerable -- (incapable of being surmounted or excelled; "insuperable odds"; "insuperable heroes")

Sense 2
surmountable, climbable -- (capable of being surmounted)

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

Similarity of adj surmountable

2 senses of surmountable

Sense 1
surmountable (vs. insurmountable) -- (capable of being surmounted or overcome; "situations of measurable and surmountable danger")
       => conquerable, superable -- (capable of being surmounted or excelled)
          Also See-> conquerable#1

Sense 2
surmountable, climbable -- (capable of being surmounted)
       => passable (vs. impassable) -- (able to be passed or traversed or crossed; "the road is passable")