Good...but...
I enjoyed the idea behind it. But it needs more. Instead of simply giving me an incorrect, highlight the correct definition so I don't have to go searching for it. Also add a counter in the top of how many questions there are and how many I have left. About halfway through I gave up to see if there was an end. Also make sure the words are spelled correctly. I mean misspelling things in an english test. Really.
All in all a great concept, clean it up and it will be a good game.