That sounds interesting and useful.
If something similar doesn’t exist already, I’d be willing to take a stab at it (the API exposes “parts of speech” for vocabulary so it shouldn’t be too difficult).
I’ll give it a few days in case someone is able to turn something up, but I don’t see anything on the curated list. (Or should that be @Kumirei -ted?)
If I end up writing this, I’ll probably only display the info after hitting a keystroke (perhaps ‘opt-h’ or something for “hint”) rather than displaying it all the time. I could be persuaded to make it an option to always display or not.