Definition of unmotorable in English:

unmotorable

Pronunciation /(ˌ)ʌnˈməʊt(ə)rəbl/

adjective

West African, Indian
  • Of a road, etc.: not suitable for or usable by a motor vehicle.

Origin

Early 20th century; earliest use found in George Dixon Abraham (1871–1965), photographer and rock-climber. From un- + motorable.