Hi. I thought of this idea randomly and I think it'd be super handy, although I'm not sure if it exists already.
A client-side mod that allows you to add a word to a filter, and checks the message you're about to send in chat- if it contains that word, the message is not sent at all. This would be useful for servers where cursing is not allowed, and can even earn you a ban. It's not like you're bypassing 'being punished' either, since the word is removed before it is sent to the server, it's like you never typed it.
(There is also another way I thought of, but that might be a bit harder. Maybe instead of blocking the sentence entirely, the blacklisted words are removed from the sentence and the rest of the message is sent, without those words. But the first option is just as good! :))