extremist
nounUK /ɪkˈstriːmɪst/
US /ɪkˈstriːmɪst/
A person who believes in ideas that are very far from what most people think is fair or right.
The police stopped the extremist before anyone got hurt.
OTHER MEANINGS
2. A person who holds extreme political or religious views.
The group was banned for spreading extremist ideas.
3. Someone who goes far beyond what is usual or moderate in their beliefs.
He was called an extremist for refusing any compromise.
4. Relating to or supporting extreme views.
The newspaper warned about extremist groups online.