A dystopia (alternatively anti-utopia) is the antithesis of a utopian society. A dystopian society is usually characterized by an authoritarian or totalitarian form of government, or some other kind of oppressive social control.
An anti-utopian society where, instead of a paradise, everything has gone wrong in the attempt to create a perfect society.
The negative outcome and eventual failure of a society which has attempted to create the perfect society.
The novels, Brave New World (Aldous Huxley) and 1984 (George Orwell) are examples of dystopian societies.