Love this add-on. For anybody reading this that has issues, one thing I have found is that

THIS ADD-ON STOPS WORKING WHEN YOU'RE ON A VPN.

So if you have disabled/enabled, removed/downloaded, changed settings, etc. trying to figure out why it isn't working, that is one possibility. I can't verify if this is true for all VPN services, just some.

Wow, you can view definitions of the definitions. Amazing.

this is absolutely amazing, you godsend of a human being, my life is changed forever , thank you SO MUCH

good

Works great, gives definitions as it's supposed to. Overall makes reading for a non-native person easier.