How do I remove a group in Linux?

Deleting a Group in Linux

To delete(remove) a given group from the system, invoke the groupdel command followed by the group name. The command above removes the group entry from the /etc/group and /etc/gshadow files. On success, the groupdel command does not print any output.

How do I remove a user from Sudo group?

If there is a user you created that you no longer need, it is very easy to delete it. As a regular user with sudo privileges, you can delete a user using this syntax: sudo deluser –remove-home username.