Nihilism

The key idea of Nihilism is the lack of belief in meaning or substance in an area of philosophy. For example, moral nihilism argues that moral facts cannot exist; metaphysical nihilism argues that we cannot have metaphysical facts; existential nihilism is the idea that life cannot have meaning and nothing has value—this is the kind that most people think of when they hear the word.

…but is also the leading philosophy among angsty teens who misunderstand Nietzsche.