The Greek adjective allotrios (ἀλλότριος) means belonging to another person, foreign, strange, or alien. It contrasts with what is one's own (idios). It can describe foreign nations, another person's property, or spiritual alienation.
Allotrios appears in John 10:5 in the Good Shepherd discourse: 'But they will never follow a stranger (allotrioo); in fact, they will run away from him because they do not recognize a stranger's voice.' The sheep know their shepherd's voice and flee from foreigners. This is a picture of spiritual discernment and intimacy — the believer who truly knows Christ can distinguish his voice from impostors. Hebrews 11:9 describes Abraham living 'as a foreigner (allotrian) in the promised land' — the posture of the pilgrim who holds earthly dwelling loosely.