Radicalism (noun)

1. The holding of radical views or the advocacy of radical political or social reforms.
2. The principles or tactics of radicals.

Origin:

Early 19th century: from radical + -ism.

Examples:

1. He was accused of radicalism and thrown in prison.
2. The party has been moving away from radicalism for years.
3. The protest was a reaction against the government's radicalism.
4. The radicalism of the feminist movement.
5. He said that the increase in crime is a result of the radicalism in the society.