Setting word dictionary
Wordlist editor of
dictionary window

Changing words in
To get to the word-editor, you need to choose Configure Dictionary. For each level there is own list of the words, as for easy, medium and hard. The word editor is [for now?] just a plain text editor, that you just put words into them. The separator is a line divider, or press Enter.
The editor will refuse to read blank lines or lines with equal letters and characters. To save the words, just press OK or Save words. You don't need to be a superuser for the program to change the words, because the dictionary files are saved into local user configuration.