The Unpublish feature will completely remove a page from your live site without deleting it. You can also use it to make sure that a page you are working on doesn't go live before you are ready.
If you are wanting to keep a page live but hidden, you can find out how to do so in this article here.
Prevent/Remove a Page From Publishing
1) To prevent or remove a page from publishing, simply click on the three dots to the right of the page's name in the left side Site Panel. Then, in the drop down menu that appears, toggle the Publish option.
2) Next, be sure to publish your design so that this update reflects on your live site.
3) That's it! The unpublished page or pages will be removed from your live site and will not go live when you publish until this setting is toggled back on.
Remove a Previously Published Page From Google
Keep in mind that if you have previously published a page and would like to prevent it from being found in Google's search engine now, you will have to ask Google to re-crawl your site in order to remove it from Google's indexing.
If you search "How do I have Google re-crawl my URLs?" Google will point you toward the next steps in order for your site to be re-crawled. Once this is done and Google has had time to update their indexing, your unpublished pages will no longer show if someone searches for them in Google.