Slander of title is quite the unique cause of action. As the name implies, it involves defamatory or slanderous activity but not against any person or personal interest. Instead, a slander of title involves activity that calls the state of your title into doubt (by, for example, filing an unwarranted lis pendens) that diminishes the value of your property.
In these situations, parties have the ability to sue for slander of title. The suit is usually accompanied by an action to clear a cloud on the title or to quiet the title, but the gist of it is quite simple: compensation for the injurious activity to the state of one’s title.