Answer:

NIHILIST

AnswerCrossword Clue
NIHILIST"Think nothing of it" sayer?
NIHILISTUltimate nonbeliever
NIHILISTRussian adherent of anarchy.
NIHILISTAdvocate of violent revolution.
NIHILISTBeliever in mob rule
NIHILISTBeliever that life is meaningless