General:
* Outwit
* Outmaneuver
* Outplay
* Outdo
* Outfox
* Trick
* Deceive
* Outmaneuver
* Get the better of
* Outflank
* Surpass
More formal:
* Circumvent
* Subvert
* Outwit
* Outmaneuver
More informal:
* Outsmart
* Outfox
* Hoodwink
* Con
* Bamboozle
More specific:
* Outthink: To be more clever or intelligent than someone else.
* Outstrategize: To come up with a better plan or strategy than someone else.
* Outplay: To be more skilled or cunning in a game or competition.
* Outwit: To use cleverness or cunning to gain an advantage over someone.
The best synonym for "outsmart" will depend on the specific context in which you are using it.