(a.) Incapable of being passed over, surmounted, or overcome; insuperable; as, insurmountable difficulty or obstacle.
Thesaurus Entries
beyond one, impassable, impracticable, impractical, indomitable, inoperable, insuperable, invincible, too much for, unachievable, unattainable, uncompassable, unconquerable, undoable, uneffectible, unnegotiable, unperformable, unrealizable, unsurmountable, unworkable
