A better solution for yourself would be just to mask the bad words (unless you really don't want to send the email).

Just do a preg_replace of *@!>&^ (or however many characters are in the badword).

Nothing much wrong with your code though, just a few logic changes might benefit yourself.

You are not validating your mail() function either. I suggest wrapping it in an IF statement or use the @ character eg: @mail(..);

Cheers