There are many issues with censorship, that'll try to avoid here, and I'd liek to extend the ideas already discussed in how to remove profanity

I think you'd get a lot of false matches on perfectly harmless language, so you need to gaurd against a lot of these without annoying people (IMHO, you'd annoy more people by punishing innocent than not stopping profanity)

The classic example I always use is my friend Dick from Scunthorpe. He has a pet Ass (as in donkey).

Now there are (at least) three false trigers in that paragraph (although some things like "c ex" might trigger more), and leads on to dialect; In UK English, an Ass is nothing but a donkey. You sit on your Arse, but getting drunk is being rat-arsed.

Perhaps on alternative is to match against bad, then match against that bad word's "safe" list (with words like Scunthorpe)

Ultimately there are going to be mistakes, and the only perfect way to do it would be human; although I'd be interested in developing an AI engine that could be taught...

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RatArsed