Remove specific commands from the in-game command suggestions.
Note: Just because the commands are hidden, doesn't mean they can't be executed. You still need to make sure to have proper permission management in place.
Put phar from Poggit into plugins folder
Edit the config.yml file located in plugin_data/HideCommands
Choose whitelist or blacklist mode
Select the commands to whitelist/blacklist
The permission hidecommands.unhide allows players to see hidden commands again.
It has been set to default: false, which means you need to explicitly give it to a player or group using a permission manager like PurePerms.