1. the beliefs or actions of people who favor rapid and sweeping changes in laws and methods of government
Usage: political
2. the quality or state of being radical or extreme in views or actions

Examples

• The professor studied the rise of political radicalism in the 1960s.
• His radicalism made him unpopular with moderate voters.
• The movement’s radicalism frightened many establishment politicians.
• She was known for her radicalism on environmental issues.
• The party distanced itself from any form of radicalism.
• Economic radicalism emerged during the Great Depression.