General Opposites:
* Divide: To separate into parts or groups.
* Fragment: To break into pieces or parts.
* Separate: To put or keep apart.
* Disunite: To break up a unified group or force.
* Disintegrate: To break apart into small pieces.
More Specific Opposites:
* Differentiate: To show or find the differences between things.
* Diversify: To make something more varied.
* Polarize: To create a division between opposing groups.
* Antagonize: To make someone hostile.
Example:
* Unify: To bring together different groups of people.
* Divide: To separate groups of people.
The best opposite will depend on the specific situation.