It seems the word a_s_s is being blocked even when those three letters are used together in other words such as cla_ss. Just take a look at this thread:

http://www.addforums.com/forums/showthread.php?s=&threadid=3815

I checked that thread and others in the College forum before and there wasn't that problem so it looks to be a recent change. Anyone know if this will be fixed in the near future?

It has been fixed.

I just entered the word "cl***ic" into a post and wondered why it "previewed" as "cl***ic" - then I read some more posts and realized what was going on. That was 10 minutes ago.
I personally think restricting the word is a little prissy - the word is used on daytime talke shows!
But if the word offends you and you want to keep the edit, you could change the edit to look for the 3 letters preceeded by a blank space or line feed and followed by punctuation, line feed, or whatever.

The problem is being worked on .