you could check for permission when they execute any command, so long as you give all your commands a permission. If they don't have permission, send " " - nothing.
https://docs.skunity.com/syntax/search/id:2054

 

Try using this:

Code (Text):

1. on command "/examplecommand":
2.    set {SOMETHINGRANDOM::%player%} to true
3.  

That will just set some random variable to true, and it will not display any message at all (not even blank one). Hope this works for you.

Or, maybe this is even better idea, if you want to completely block the command use (without any messages or variable sets):

Code (Text):

1. on command "/examplecmd":
2.    cancel event

 

No problem! If you need any help in the future, contact me