* Allow: This is the most straightforward opposite, meaning to permit something.
* Permit: Similar to "allow," it means to give permission for something.
* Authorize: This implies formal permission or approval.
* Enable: This suggests making something possible.
* Encourage: This implies promoting or supporting something.
* Sanction: This refers to official approval or acceptance.
The best word to use depends on the specific situation and the nuance you want to convey.