nihilism

1. The view that all endeavours are devoid of objective meaning. (uncountable)
2. The rejection of, or opposition to, religious beliefs, (inherent or objective) moral principles, legal rules, etc., often due to the view that life is meaningless (sense 1). (uncountable)
3. The rejection of non-proven or non-rationalized assertions in the social and political spheres of society. (uncountable)
4. A delusion that oneself or the world, or parts thereof, have ceased to exist. (uncountable)
5. A doctrine grounded on the negation of one or more meaningful aspects of life; in particular, the view that nothing in the world actually exists. (countable, uncountable)
6. Something that is regarded as meaningless. (countable)

Plural nihilisms