Definitions for radicalismˈræd ɪ kəˌlɪz əm
Random House Webster's College Dictionary
rad•i•cal•ismˈræd ɪ kəˌlɪz əm(n.)
the holding or following of radical views or principles.
the principles or practices of radicals.
Origin of radicalism:
the political orientation of those who favor revolutionary change in government and society
Any of various radical social or political movements that aim at fundamental change in the structure of society
the quality or state of being radical; specifically, the doctrines or principles of radicals in politics or social reform