At first glance, this may seem silly, but some of the translations in the C-E dictionaries are words even I, with 9 years of college and an advanced degree, and many, many years of compulsive reading, don't know. When I DO look these words up, some of them are terms of art or professional terminology and some are arcane synonyms for everyday words. I can't think of any examples right now, though. Sorry.
I probably would look up more of those words if I didn't have to open another program to find out.
Clearly, not an essential feature, but it would be useful.