General antonym:
* Stranger: This is the most general antonym, meaning someone who is not related or known.
Antonyms based on specific meanings:
* Individual: If you're talking about family as a unit, the opposite could be an individual person.
* Enemy: If you're thinking of family in terms of loyalty and support, the opposite could be an enemy or someone who is opposed to you.
* Loneliness: If you're considering the feeling of being part of a family, the opposite might be loneliness or isolation.
It's important to consider the specific context when choosing an antonym for "family."