General Antonyms:
* Individual
* Independent
* Sovereign
* Self-governing
* Autonomous
* Free
* Uncontrolled
Antonyms in the context of living organisms:
* Solitary
* Individualistic
* Lone
* Scattered
Antonyms in the context of settlements:
* City-state
* Nation
* Country
* Independent state
Antonyms in the context of power and control:
* Domination
* Control
* Empire
* Conquest
It's important to consider the specific context of the word "colony" to choose the most appropriate antonym.
For example, if you're talking about a colony of ants, "individual" or "solitary" might be the best antonyms. But if you're talking about a colonial empire, "independent state" or "nation" might be more appropriate.