This is just what I was looking for, this extension is amazing. All aside, I think that it can be improved further by two things, first the loading time until the result shows up is a little bit long, second, I would love the results to stay up when I switch to other tabs.

Wow! very helpful Addon! and gives a lot of information. I just selected/highlighted a word and I clicked on the extension button/icon on the top toolbar, and a popup window showed up explaining the word i chosen.
Also your website is very well designed and very helpful! 👍
* One suggestion: it would be perfect if when we Right-click our mouse on the selected word, the "context menu" will show up, and we click the icon from there as well.