The relevant documentation on this is confusing at best.
The behaviour page has the notice:
Please note that expletives are not allowed. If you use expletives on this site, you may be issued a warning or a suspension.
may be issued a warning or a suspension. portion of the page is a direct link to a meta question about "profanity" on stack-exchange in general that directly disagrees with the linking text. In response to the question
Are expletives allowed on SE sites?, the highest-voted answer is
Yes, but keep them to a minimum.
As far as I can tell, I would assume the behaviour page is out of date, since it seems the community consensus disagrees with it.