[Exolent[jNr]]

It's all about the patterns and match indexes.

Here's an example:
^.*fuck.*$

That is a simple one saying that players cannot say "fuck"..

If you wanted to white list a word or pattern for this:
1. Add parenthesis around your word in the pattern for the swear filter: ^.*(fuck).*$
2. Count the number of open parenthesis it takes to reach your word: 1
3. Use this new pattern as the swear filter, and this number is your match index.
4. Add a white list that will match "fucking": /fucking/

That's it.