D defs.my
Entry 1 sense Webster, 1913

Insurmountable

/ĭnˌ-sẽrm-oun'-təb-əl/ · In·sur·mount·a·ble · IPA /ˌɪnsərmˈaʊntəbəl/
01 a. Incapable of being passed over, surmounted, or overcome; insuperable; as, insurmountable difficulty or obstacle.
  1. 1.
    Incapable of being passed over, surmounted, or overcome; insuperable; as, insurmountable difficulty or obstacle.
    “Hope thinks nothing difficult; despair tells us that difficulty is insurmountable.” I. Watts.