Remove a User from a SharePoint Group from Site Permissions:

  1. Navigate to the site where the group will be used.
  2. On the site’s home page select Site Permissions from the “Site Actions” menu.
  3. Select the group from which users will be removed.
  4. Click on the user(s) to be removed.
  5. Click on the down arrow next to the Actions option to open the menu.
  6. Select Remove Users from Group on the Actions menu.
  7. On the dialog confirmation prompt click OK to confirm the action.