If you describe a person or thing as sui generis, you mean that there is no-one else or nothing else of the same kind and so you cannot make judgments about them based on other things. Japanese politics are sui generis. = unique
constituting a class of its own; unique; "a history book sui generis"; "sui generis works like Mary Chestnut's Civil War diary"
Latin for "of its own kind;" hence, whatever is absolutely unique or distinctive about something Also see noesis