I bet it'd be pretty easy to make an awk script to convert XML into something like dictfmt(1)'s -j Jargon File format text.

https://linux.die.net/man/1/dictfmt http://www.catb.org/jargon/oldversions/jarg447.txt

Maybe. Don't know. I've never really used dictfmt or the like.

What's it good for?

once you get the dictd server set up, all you need to do to get a definition is run curl. google 'curl dict' for some stuff.