There is no walkthrough for the demo. If you still need another hint: when you figure out what is the synonym of "nothing" based upon the second hint, the solution should become clearer.
Sorry, but it doesn't. Every synonym I can think of, of nothingness based on the idea of "increment" doesn't make a word/phrase in the box. I'm trying, but it's just not making sense to me. It's just a shame if there's no answer key since it cuts me off from the rest of the demo so soon.