Board Thread:Support Requests - Getting Technical/@comment-5175866-20130310000410/@comment-3335785-20130312003722

Censoring words is possible, but complex. I don't know if anyone has a working script that does it right now. Regardless it'll either need to take advantage of Monchoman45's chathacks which would then need to take advantage of the undocumented extensibility, or import scripts into chat using a more global hack, outlined Help:Custom Chat Javascript/CSS. Either way, finding someone to make such a script isn't going to be easy.

A far easier way is to use MediaWiki:Emoticons. Simply add the words you want to filter below the image you want to display and the words will be covered up. Hovering over the image will show what was typed, but that's probably the best option right now.