relating to or denoting to an imagined state or society where there is great suffering or injustice - the dystopian future of a society bereft of reason.
Basically it describes a world after we have blown each other up with nuclear weapons, or after a major disaster like global warming or total lack of ice cream or something terrible like that. In that world, few people survive and, according to the films, they live in wild small gangs fighting each other like wolves and scrapping for every bit of food or clean water to drink.
I would hate to live in such a world, wouldn't you?
If I were that unfortunate to be there I would try to earn a living by making ladies razors because, according to the films, the women all have their under-arms shaved. Their clothes may be dirty, and their hair unkempt, but their underarms are always shaved. Their legs too. The men invariably grow beards over time, and wear indestructible trousers that do not rip or tear at the back, and with unbreakable zips; yet the women always have shaved underarms. How do they do that?
I think I'd either make ladies' razor blades or men's trousers. Blades are easier, all you have to do is sharpen a piece of metal.
What would you do to make a living in such a world? Make toothpaste perhaps? The people in the films may be ragged and dirty but they all have bright clean teeth.