Collocations for radical - adj.

be, seem, sound
become

extremely, fairly, very, etc.
increasingly
equally
insufficiently
genuinely, truly
a truly radical concept

potentially
politically, socially
When I was young, I was more politically radical.

Radical is used with these nouns:
agenda, alteration, alternative, challenge, change, coalition, critique, demand, departure, development, difference, extremist, faction, feminism, feminist, fringe, idea, ideology, implication, improvement, innovation, liberal, liberalism, measure, message, move, movement, Muslim, nationalism, nationalist, nature, overhaul, party, politics, preacher, programme, proposal, reappraisal, reconstruction, reform, regime, reorganization, rethink, revision, rhetoric, right, sect, shake-up, shift, simplification, socialist, solution, stance, strategy, surgery, terrorism, terrorist, thinker, tradition, transformation, turn, version, view, vision, wing