In the web application, click the 
Delete button on the toolbar
In the desktop application:
Select the Remove item in the object's context menu
Select the Group > Delete main menu item.
The tool supports interface of Foresight Analytics Platform 9 or earlier.
To delete selected groups of users in the Groups section:
In the web application, click the Delete button on the toolbar
In the desktop application:
Select the Remove item in the object's context menu
Select the Group > Delete main menu item.
NOTE. To delete a group of users, the user must hold the Changing User Permissions, Distributing Roles, Changing Policy privilege. When the role separation mode is active and the Deny Deleting Groups with Permissions to Access the Repository Objects checkbox is selected on the Access Control tab, the ISA cannot delete groups with access permissions for repository objects.
After executing one of the operations a confirmation dialog opens.
NOTE. Built-in groups of users: administrators and Users cannot be deleted.
See also:
Creating Groups of Users and Working with Them | Viewing User and Group Objects