| visitor(noun, person, relation, acquaintance, outsider) |
| alien(noun, person, relation, acquaintance, outsider) |
| antagonist(noun, opponent, adversary, foe) |
| assailant(noun, opponent, adversary, foe, antagonist) |
| opponent(noun, adversary, foe, antagonist) |
| opposition(noun, opponent, adversary, foe, antagonist) |
| outsider(noun, person, relation, acquaintance) |
| arch enemy(expression, opposition, opponent, enemy, foe) |
| avowed enemy(expression, opposition, opponent, enemy, foe) |
| bitter adversary(expression, opposition, opponent, enemy, foe) |
| bitter foe(expression, opposition, opponent, enemy, foe) |
| confirmed enemy(expression, opposition, opponent, enemy, foe) |
| declared enemy(expression, opposition, opponent, enemy, foe) |
| dire foe(expression, opposition, opponent, enemy, foe) |
| fast foe(expression, opposition, opponent, enemy, foe) |
| implacable enemy(expression, opposition, opponent, enemy, foe) |
| implacable foe(expression, opposition, opponent, enemy, foe) |
| mortal enemy(expression, opposition, opponent, enemy, foe) |
| mortal foe(expression, opposition, opponent, enemy, foe) |
| most ardent enemy(expression, opposition, opponent, enemy, foe) |