Still cannot seem to get the category column to show in the frontend. This was listed as a bug fix in version 1.1.1 but I have installed the component on a fresh install of Joomla 3.1.5 with no luck - the column is not there.
Okay! So it turns out I was missing something obvious!
For those that don't know - You set the fields visible in the word list (i.e. the columns) in Gnosis > Options > Words - then under "Field Order" you define the fields you wish to show. (there is a handy tooltip explaining this!)
Which fields to include in the list, and in what order, in comma separated numbers.
0 --- word
1 --- pronounciation
2 --- category
3 --- definition
4 --- added by
5 --- date created
6 --- date modified
7 --- tags
For example; To show just the word and definition, enter 0, 3