OS X how to disable Command P Shortcut
Keyboard shortcuts such as the "Print Document" shortcut are baked into each application, so unfortunately it isn't something that is system-wide and can be disabled in one place. 

Here's an excerpt from Apple's Keyboard Shortcut page:


  To learn more shortcuts, check the menus of the app you're using.
  Every app can have its own shortcuts, and shortcuts that work in one
  app may not work in another.


However there is still a workaround to get shortcuts from working, and that would be by using another application that binds shortcuts. By binding Command+P to do nothing on another application you would essentially block it from being able to do anything else. To learn more on how to do this, check out this very similar question: How to disable keyboard shortcuts in mac os x