Hi there, this is a really good idea!! I would need a tool like this. Most importantly it is not possible to edit the original word (which very like is highly inflected, I'd rather like to add the base form). I also wonder if the word list should be stored within the Add-On permanently. I fear that it will slow down the browser once the list grows.

An Add-On for Chrome that I adore (but can't get to work with Firefox) is https://chrome.google.com/webstore/detail/speed-learning/mgoebobcfmlecmnkediacjlofmbeihaf

I stores lists of words and phrases to a google docs table. (There is room for improvement here, too, as I'd rather use shortcuts than right mouse click selection menues, and the "done" window is annoying.)

I will definitely watch your Add-On for progress. All the best.

Works great, EXCEPT I can't figure out how to get it to recognize long words. Let's pretend I have the Icelandic word lögreglumaðurinn, it's actually 4 different words: lög (law), reglu (order), maður (human), inn (the) (=policeman). I need it to be able to recognize all of these 4 separate words which I've put into the "dictionary" separately. Or let's pretend I have the Indonesian word "melihat" (me "verb", lihat "see" = sees), I need it to recognize "lihat" even when "me" is there, as "me" is a separate word. If this gets fixed (or if it's already possible, if it gets better explained in the FAQ) I'll definitely give this 5 stars.