By default, the Mac launchpad shows all the applications installed on your system from the app store. It can also contain shortcuts to other applications that you have manually installed (Added by dragging the app to the launchpad). To remove apps installed from the app store, click and hold on the icon till it starts shaking and a remove button (x) appears on the top of the icon. Click the remove button to remove the app from the launchpad and from the system.
For manually installed applications, first remove the app manually by deleting the app from its location. Now a question mark will appear on the app icon in the launchpad. Drag this icon to the trashcan to permanently remove it from launchpad.
Another way to remove applications is to open the finder, navigate to the applications folder on the left and then right click on the icon and select “Move to trash”. This will remove the app from the launchpad also.
All the above methods are tested on Mac Yosemite, Mac Mavericks and Mac El Capitan.