D defs.my
Entry 1 sense Webster, 1913

Insuperable

· In·su·per·a·ble · IPA /ɪnˈsup(ə)ɹəb(ə)l/
01 a. Incapable of being passed over or surmounted; insurmountable; as, insuperable difficulties.
  1. 1.
    Incapable of being passed over or surmounted; insurmountable; as, insuperable difficulties.
    “And middle natures, how they long to join, Yet never pass the insuperable line?” Pope.
    “The difficulty is enhanced, or is . . . insuperable.” I. Taylor.