lunatic fringe

American  

noun

1. members on the periphery of any group, especially political, social, or religious, who hold extreme or fanatical views.

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lunatic fringe British  

noun

1. the members of a society or group who adopt or support views regarded as extreme or fanatical

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lunatic fringe Cultural  

1. Derogatory name for the extreme radical members of a group, especially in politics: “The candidate referred to the organization as being on the lunatic fringe of conservatism.” The term was coined by Theodore Roosevelt.

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Etymology

Origin of lunatic fringe

An Americanism dating back to 1910–15