To block a Discord user on desktop,
right-click on their username
and select "Block" from the drop-down menu.
On mobile, tap their profile picture,
followed by the ellipsis, then tap "Block."
With this user blocked,
they'll no longer be able to ping or tag you in the chat.
If this user was on your friends list,
they will be automatically removed.
In shared channels with the blocked user,
their messages will be hidden by default.
To view any of those messages, click or tap to show them.
When a blocked user tries to send you a direct message,
they'll receive an error message
and be unable to send the message to you.
Discord will not send them any notification
alerting them that they were blocked.