D defs.my
Entry 1 sense Webster, 1913

Impassable

/ĭmˌ-păs'-əb-əl/ · Im·pass·a·ble · IPA /ˌɪmpˈæsəbəl/
01 a. Incapable of being passed; not admitting a passage; as, an impassable road, mountain, or gulf.
  1. 1.
    Incapable of being passed; not admitting a passage; as, an impassable road, mountain, or gulf.