General synonyms:
* Replaced
* Displaced
* Superseded
* Overthrown
* Ousted
* Dethroned
* Taken the place of
* Removed
More specific synonyms:
* If referring to power or authority: Overpowered, usurped, overthrown
* If referring to ideas or beliefs: Discredited, undermined, challenged
* If referring to a physical object: Replaced, substituted, exchanged
* If referring to a habit or routine: Replaced, superseded, abandoned
Example sentences:
* The new CEO supplanted the old one. (Replaced)
* The modern theory supplanted the older one. (Superseded)
* The old building was supplanted by a new one. (Replaced)
* Her unhealthy habits were supplanted by a healthy lifestyle. (Replaced)
The best synonym will depend on the specific situation and the nuance you want to convey.