Source : Webster's Revised Unabridged Dictionary (1913)

Nihilist \Ni"hil*ist\, n. [Cf. F. nihiliste. See {Nihilism}.]
   1. One who advocates the doctrine of nihilism; one who
      believes or teaches that nothing can be known, or asserted
      to exist.

   2. (Politics) A member of a secret association (esp. in
      Russia), which is devoted to the destruction of the
      present political, religious, and social institutions.

Source : WordNet®

nihilist
     n 1: someone who rejects all theories of morality or religious
          belief
     2: an advocate of anarchism [syn: {anarchist}, {syndicalist}]