If "exhibit" means to display or showcase:
* Conceal
* Hide
* Suppress
* Withhold
* Secret
If "exhibit" means to demonstrate or prove:
* Disprove
* Refute
* Contradict
* Deny
* Conceal
If "exhibit" is used as a noun referring to a displayed item:
* Hidden object
* Undisclosed item
* Secret
To give you the most accurate antonym, please provide me with the sentence or context in which "exhibit" is used.