I used to work on the project, where we had a filter like this on people's names, to prevent abuse. We quickly learned that showing message like "Name cannot c

I used to work on the project, where we had a filter like this on people's names, to prevent abuse. We quickly learned that showing message like "Name cannot contain profanity" is a bad idea, because we'd show this due to names that happen to be "questionable in some contexts". People get pissed off real quick, if you tell them they have "profanity" in their name. We changed it to something like "you're using a word we don't allow" (avoiding mentioning of "profanity" altogether), PLUS, we added a way for users to quickly contact support, if they're in this pickle.