How to hide restricted website names on iPad's Content & Privacy Restrictions?

There are several websites I have restricted on my kids iPad but unfortunately they are visible to them and some website has adult content names and I don’t know how to restrict them and keep them invisible to kids.

[Re-Titled by Moderator]

Original Title: Want to hide names of restricted website names on content and restrictions as they are not appropriate for kid to see but I still want to restrict them