Etymology
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centrist (n.)

1872, from French centriste, from centre (see center (n.)). Originally in English with reference to French politics; general application to other political situations is by 1889.

Where M. St. Hilaire is seen to most advantage, however, is when quietly nursing one of that weak-kneed congregation who sit in the middle of the House, and call themselves "Centrists." A French Centrist is—exceptis eoccipiendis—a man who has never been able to make up his mind, nor is likely to. ["Men of the Third Republic," London, 1873]
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centrism (n.)

"policy of taking a middle position between extreme views," 1921, in communist and socialist writings, from centre + -ism (also see centrist).

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