Adjective
Without a companion.
Source: Webster's dictionaryOften you shall think your road impassable, sombre and companionless. Have will and plod along; and round each curve you shall find a new companion. Mikha'il Na'ima
(Title: To the Moon) Art thou pale for weariness Of climbing heaven, and gazing on the earth, Wandering companionless Among the stars that have a different birth,-- And ever-changing, like a joyless eye That finds no object worth its constancy? Percy Bysshe Shelley