* If you're thinking about biological life: The opposite could be non-living (like a rock or a table).
* If you're thinking about movement and activity: The opposite could be dead or inanimate.
* If you're thinking about being a living creature: The opposite could be plant (though plants are living things too!).
* If you're thinking about something specifically bred or raised: The opposite could be wild animal (though even wild animals are still alive).
So, the answer depends on the context! What were you thinking about when you asked?