Cool idea, Sawyer. I think you're going to have to have two textboxes. I'll call them front (the word) and back (the definition). Choose an animation that's closest to the flip you want (swivel is the closest I can find) and then have "front" swivel and then disappear. Set it up so "back" begins to swivel at the same time "front" does.

While you're getting the timing right, offset the two graphics so you can click on both at will. Once you've got them playing correctly, put "front" in front of "back" so it will be the only thing people see on the slide.

Let me know if this doesn't seem as clear to you as it does to me.