General Antonyms:
* Conceal: To hide or keep secret.
* Hide: To keep from sight.
* Suppress: To prevent from being known or expressed.
* Mask: To cover or disguise.
* Obscure: To make unclear or difficult to understand.
* Withhold: To refuse to give or provide.
More Specific Antonyms:
* Disguise: To change the appearance of something to deceive.
* Dissemble: To conceal one's true feelings or intentions.
* Encrypt: To convert information into a code.
* Censor: To remove parts of something considered objectionable.
The best antonym for "reveal" will depend on the specific situation and the intended meaning.