No, this is not a feature available within ClassiPress. I'm unsure if there are plugins which may achieve what you are asking in terms of blocking words etc, but there are plugins such as
wp-ban where you can block IP ranges, specific addresses, or host addresses etc. Other members of the community have found methods of preventing spam by using various captcha plugins.. Otherwise it would be some sort of customization on your part to build a word filter in or edit .htaccess to block certain countries perhaps?