Q: How do I HIDE an app that I have purchased.....

You cannot hide an installed App on the iPhone.

You can hide a purchase from the general Purchase list, but you need to do it from a computer, it cannot be done directly on the iPhone:

Hide and unhide purchases in iTunes or iBooks on your Mac or PC - Apple Support

I edited by response above, You cannot hide Apps on the iPhone. The most you can do is put them in a folder, by dragging them onto another App.

Put your finger on an App and hold it until they all start shaking, then drag the App onto another App to create a folder.  Once the folder appears remove your finger form the screen.

Press the Home button to complete the action.

No. Other than placing it in a folder, or moving to an alternate Home screen (or both), you cannot hide an app.

angelarnold2003 wrote:

 

Okay....Got it. Is there a way to "hide" the app from prying eyes?

Put a passcode on your phone.

As I said before, No. You cannot hide installed Apps on an iPhone. If you do not want an App being seen by others. don't lend your iPhone to others.

When you tap and hold the app icons to move them around on the screen, you can also drag them to the right edge and "create" a n alternate home screen and place it there (folders can be moved as well).

http://help.apple.com/iphone/9/#/iph822ece7dd

Not only can you not do that now, you never could in iOS.