Formal:
* Expel: This emphasizes the forceful removal from a place or position.
* Eject: Similar to expel, but often used for removing someone from a building.
* Dismiss: This suggests a formal removal from a job or position.
* Depose: This implies the removal of someone from a position of power or authority.
* Unseat: This is often used in the context of political elections, where someone is removed from office.
Informal:
* Kick out: This is a more casual way of saying "oust."
* Throw out: Similar to "kick out," but can also be used to describe removing something unwanted.
* Boot out: Similar to "kick out," but more informal.
* Force out: This emphasizes that the removal is against the person's will.
* Get rid of: This is a general term for removing something unwanted.
The best synonym for "oust" will depend on the specific context.