This is a perfect pop-up dictionary add-on and I have been searching for such kind of stuff from past two weeks.
Although as an improvement I would like it to have a "SAVE WORD" button to look up the list later on. It will help improve my vocabulary as well.
I will not forget to rate it five star if that as well is implemented. Although I have to admit that at this point of time as well it is a piece of art.