-domain-workgroup is a parameter for vserver active-directory show command.
[-domain-workgroup <CIFS domain>] - NetBIOS Domain/Workgroup Name. If you specify this parameter, the command displays information only for the Active Directory accounts that are in the specified NetBIOS domain or workgroup
In the cifs modify command, you can use.
| [-workgroup <NetBIOS>]} - Workgroup Name .This parameter specifies the name of the workgroup (up to 15 characters).
More about Workgroup. How to convert a CIFS SVM from a domain membership to workgroup