* Disclosed: This is the most direct opposite, meaning something has been revealed or made known.
* Revealed: Similar to disclosed, this means something hidden has been made public.
* Known: This indicates that something is familiar or understood.
* Public: This refers to information that is available to everyone.
* Open: This suggests that something is not secret or hidden.
The best antonym will depend on the specific situation and the meaning you want to convey.