NodeBB permissions are additive only, there are no negative permissions such as denying a specific user or group.
Sorry to bump an old topic; are there any plans to implement such a feature anyway? Or is there a way we can build this ourselves? Its a pain right now to organize birthday gifts and allow everyone but one person.
I am new in nodebb, but I really like it. The only problem I have encountered so far is the card slider. Could you tell me how I can add this so my "Recent topics" look exaclty the same way as in the community.nodebb.org?