Another variant which definitely works is using the K4PC app to get dictionaries, then treat them in a way so you can put them on the Kindle. This is on the edge of what is allowed to discuss here, so you have to put the loose ends together by yourself. Anyway, here is a reference to the thread where it was initially discussed:
https://www.mobileread.com/forums/sho...d.php?t=168044
The method works for all dictionaries supported in the K4PC application. (Clarification: IIRC, that's Oxford/Oxford American/german/french/italian/spanish ones; I may have missed some).