nihilism Meaning, Definition & Usage

  1. noun a revolutionary doctrine that advocates destruction of the social system for its own sake
  2. noun the delusion that things (or everything, including the self) do not exist; a sense that everything is unreal
    nihilistic delusion.
  3. noun complete denial of all established authority and institutions

WordNet

Ni"hil*ism noun
Etymology
L. nihil nothing: cf. F. nihilisme. See Annihilate.
Definitions
  1. Nothingness; nihility.
  2. The doctrine that nothing can be known; scepticism as to all knowledge and all reality.
  3. (Politics) The theories and practices of the Nihilists.

Webster 1913