Nihilism is a philosophical doctrine suggesting the negation of one or more putatively meaningful aspects of life. It has several forms:

• Existential nihilism, the theory that life has no meaning
• Mereological nihilism, disbelief in objects with proper parts
• Metaphysical nihilism, the belief that there is a possible world in which there are no concrete objects at all
• Epistemological nihilism, disbelief in knowledge
• Moral nihilism, disbelief in objective moral facts
• Political nihilism, the rejection of the necessity of fundamental social or political structures

Nihilism may also refer to:

• Russian nihilist movement, a cultural and philosophical movement in Russia from the late 19th century
• "Nihilism", a song by Rancid from their 1994 album Let's Go