If you no longer use a workspace but don't want to delete it, you can archive it instead. Unlike deleting, archiving can be undone: you can unarchive the workspace at any time.
Once a workspace is archived, it's hidden and can't be accessed until you unarchive it.
How to archive a workspace
Go to Settings → Workspace settings.
Click Edit Workspace next to the workspace you want to archive.
Scroll down, tick the Archive workspace checkbox and click Save settings.
Where to find archived workspaces
Archived workspaces no longer appear in the Workspaces tab. You can still find them in Settings → Workspace settings, marked with the label "archived".
How to unarchive a workspace
Open the archived workspace in Workspace settings, untick the Archive workspace checkbox and save.
Note: Only Administrators can archive or unarchive workspaces.