extremist
noun
[ ɪkˈstriːmɪst ]
• a person who holds extreme political or religious views, especially one who advocates illegal, violent, or other extreme action.
• "political extremists"
Similar:
fanatic,
radical,
zealot,
fundamentalist,
hardliner,
dogmatist,
bigot,
diehard,
militant,
activist,
sectarian,
chauvinist,
partisan,
ultra,
maniac,
crank,