extremist
This term carries a heavy negative connotation, typically associating the subject with intolerance, rigidity, or a willingness to use violence to achieve a goal. It suggests a departure from the mainstream or moderate center of a belief system, implying that the person has moved beyond reasonable debate into a zone of obsession or danger. When used outside of politics or religion, such as in health or fitness, the word shifts toward a description of obsessive discipline or an unbalanced lifestyle. In these contexts, it describes someone who pushes a practice to its absolute limit, often at the expense of moderation or health.
Meanings
A person who holds extreme political or religious views, especially one who advocates for radical change or uses violent methods to achieve their goals.
"The government is monitoring the group to ensure no extremist elements are infiltrating the organization."