nihilism

The doctrine that nothing actually exists or that existence or values are meaningless.

Relentless negativity or cynicism suggesting an absence of values or beliefs.

Political belief or action that advocates or commits violence or terrorism without discernible constructive goals.

A diffuse, revolutionary movement of mid-19th-century Russia that scorned authority and tradition and believed in reason, materialism, and radical change in society and government through terrorism and assassination.

A delusion, experienced in some mental disorders, that the world or one’s mind, body, or self does not exist.

In metaphysics, the doctrine that nothing can really be known, because nothing exists; the denial of all real existence, and consequently of all knowledge of existences or real things.

In theology, same as nihilianism.

Total disbelief in religion, morality, law, and order.

Originally, a social (not a political) movement in Russia, in opposition to the customary forms of matrimony, the parental authority, and the tyranny of custom. In this sense the word was introduced by Turgeneff in 1862. See nihilist, 3.