Hide plex library?

I made a plex library for a friend and shared with them but I don’t care to see it on mine. Is there a way I can keep it up for them but hide it from my site when I log in? The reason I made a seperate library is, I don’t want them to have access to my entire collection.

You have a Plex Pass. With Plex Pass, there is no need to create a separate library for these reasons.
Just restrict that user to particular sharing ‘labels’.
Then put that label on every item he is allowed to see.
https://support.plex.tv/hc/en-us/articles/204232573-Restricting-the-Shares

The alternative would be to create a managed user account to use for yourself, for daily use and leave the “main” account only for “administrative” tasks. This managed user then doesn’t get the additional library shared to him.

Thanks for this.

Is it possible to add a label to an entire library all at once? Also was wondering if there was a way I could hide the movie from my library that I have labeled but have it show on theirs?

It is not possible to hide anything from the Administrator’s account, nor should it be. As @OttoKerner pointed out, you can create a managed account for your own use, and share to it whatever you want to be able to see. Then use that account for your daily use, and only switch to the Admin account for administrative tasks, like adding new media.

You can select every item in the library, then add a label to every item in one step.