Extremist (noun)

1. A person who holds extreme political or religious views.
2. A person who advocates illegal, violent, or extreme actions or solutions in support of a particular cause or ideology.

Origin:

Early 20th century: from extreme + -ist.

Examples:

1. The terrorist attack was carried out by a small group of extremists.
2. The government condemned the actions of the religious extremists.
3. The extremists on both sides of the issue refused to compromise.
4. The political extremist was known for his controversial speeches.
5. The extremist group was banned due to their violent activities.