Mute/en
From xat wiki
(MUTE) - Ban silently
FOR OWNERS ONLY! Allows you to ban a user without them knowing. To mute a user click on their name and press ban, select the duration and press the mute button. NOTE: the maximum time you can mute a user for is 1 hour.
To mute a user, click on their name then click ban, input a duration and press the mute button. The maximum mute time is 1 hour.
Note: you must be an owner to use this power.