From Wikipedia, the free encyclopedia

Extremism means, literally, "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 (by the speaker or by some implied shared social consensus) to be far outside the mainstream attitudes of society. It can also be used in an economic context. The term is usually meant to be pejorative. However, it may also be used in a more academic, purely descriptive, non-condemning sense.
Extremists are usually contrasted with centrists or moderates. For example, in contemporary discussions in Western countries of Islam or of Islamic political movements, the distinction between extremist (implying "bad") and moderate (implying "good") Muslims is typically stressed.

Political agendas perceived as extremist often include those from the far-left politics or far-right politics as well as radicalism, reactionism, fundamentalism and fanaticism.

Definitions