Rated 4 out of 5 stars

Not that user-friendly, but works fine and still saves time. So I guess it deserves stars :)

This review is for a previous version of the add-on (1.4.1). 

Your comment let me thinking. Hope you like version 1.5.0. It provides a floating link to the translation when you double-click a word.

While it is approved, you can see it at
http://www.islabinaria.com/samu/wordreference-translator/?lang=en