extremist

Extremism is "the quality or state of being extreme" or "the advocacy of extreme measures or views". The term is primarily used in a political or religious sense to refer to an ideology that is considered to be far outside the mainstream attitudes of society. It can also be used in an economic context. The term may be used pejoratively by opposing groups, but is also used in academic and journalistic circles in a purely descriptive and non-condemning sense.