You can archive a space, so that its content is less visible but still available. You need to be an administrator of the space to archive it.
One of the primary reasons to archive a space is to remove the pages from the wiki search results but still allow you to review and access the content. If you want the space to be fully visible again, you can change its status from archived to current at any time.
Instructions for archiving a space are available within the Confluence Documentation.