To get all words used by a word, recursively, use

[ word-def quot-uses ] closure

Also words list>hashtable is just vocab-words

And list>hashtable can be written as

: list>hashtable [ “” ] H{ } map>assoc ;

Assuming you want “” as the values, but usually we use equal keys/values when representing a set as a hashtable:

: list>hashtable [ dup ] H{ } map>assoc ;