extremism; radicalism
Refers to political or ideological extremism; often used in news and formal contexts.
The rise of extremism is a concern.
He fell into radicalism.
過激派 refers to a radical faction or group, while 過激主義 is the ideology of extremism itself.
Islamic extremism
Compound of 過激 (kageki, 'extreme') and 主義 (shugi, 'ism'). The exact historical derivation is uncertain, but the word follows standard Sino-Japanese word formation patterns.