When I think of a dystopian society, I think of a society that is in an oppressive dictatorship or a society that is in constant fear of an entity. A dystopia is basically the complete opposite of a utopia, a society that benefits everyone in the best way possible. There are some obvious books and movies like The Hunger Games, Maze Runner, and Divergent that are classified as dystopian societies.
I think one defining feature of a dystopian society is a class of people oppressing another. This is what separates a dystopian society from a post-apocalyptic society. A post-apocalyptic society is caused by some natural or scientific event like a terrific pandemic or a zombie outbreak. However, a dystopian society has some person, group, or entity that creates the dystopian society. One example is a show called Code Geass. In this show, Britain has become a global superpower and has practically taken over the whole world. The countries they take over are classified by numbers, and the citizens are regulated to second-class citizens. I would classify this as a dystopian society since the government has no problem oppressing or killing the “former” citizens.
Dystopian societies generally create conditions where the people have little access to food, shelter, and other resources. These societies make it extremely hard to survive day to day. Their impoverished conditions don’t always have to be caused by an oppressive ruler. I believe that a dystopian society can result from a world of constant war. A true fantasy-like dystopian society could occur in real life if a full nuclear war broke out. The conditions felt in Japan after World War II would be felt across nations. There is a movie that is coming out that describes a fantasy civil war in America that leaves society very dystopian-like.
I think that the definition of a dystopia is very broad and potentially subjective since the dystopias we see come from fantasy. To classify a dystopian society is not easy, but to identify dystopian conditions is most likely easier.