How to hide an app from the Launchpad?
If you feel that your Launchpad is filled with apps, you can make folders in Launchpad by moving a app over another app.

How to do this shown at wikihow, this is done in Mac OS X Lion, but will work in Yosemite.

What the content of link describes is how to make folders in Launchpad, this is easily done by moving an app (inside Launchpad) over another app. This will make a folder with both apps in it.