/ Dictionary / Index R radicalism: Meaning and Definition of Find definitions for: rad•i•cal•ism Pronunciation: (rad'i-ku-liz"um), [key] — n. the holding or following of radical or extreme views or principles. the principles or practices of radicals. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: radicalism (Thesaurus) radical empiricism radicalize Related Content Daily Word Quiz: portent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language