Let me try
■■■■
Works here 
Seriously though, there is the
Admin → Settings → Posting - censored word
setting.
Though it could help some, don’t count on it.
Just as I posted unicode for the black squares, you’ll find that some can be very inventive at finding ways to by-pass it.
Of course if you do censor a word and someone goes out of their way to post it, you will know it was intended and not done in ignorance.
Off-Topic a bit, but until there is a way to add URLs to Screened URLs this setting works a treat at foiling link drops such as adf.ly
URLS don’t work with tricks