How to COMPLETELY hide a category?

I am currently changing the focus of my website (in maintenance now so I can’t link to it) and therefore, some categories I’ve created in the past are now pretty much redundant. For example, on my old website I’ve posted news about a certain topic, but I won’t do that with my new website. I still want to keep my news archive though, but I don’t really want it to show ANYWHERE on the website. Basically making it only available trough either google or the backend of the website. Is there a way to do that?