Administrators: Be extremely careful regarding the entries you place on this list. Simple typographical errors can block the creation of thousands of unintended usernames. Don't add a term unless you are completely sure it will not affect innocent users. For example, "EmbarassedMonkey" because it matches "ass". This is the Scunthorpe Problem. See here for general information about regexes (which are used here), and here for specific details about their use in PHP. This feature is available from an extension called Username Blacklist, written by Rob Church. Documentation can be found on the MediaWiki website.