Etymology
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Vichy (adj.)
in reference to collaborationist government of France, 1940, from the name of the city in department of Allier in central France, famous for mineral springs, seat 1940-44 of the French government formed under Nazi occupation and headed by Pétain. The place name is of uncertain origin.
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vichyssoise (n.)
1939, French, in full crême vichyssoise glacée, literally "iced cream (soup) of Vichy" (see Vichy).
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collaboration (n.)

1830, "act of working together, united labor" (especially in literature or scientific study), from French collaboration, noun of action from past-participle stem of Latin collaborare "work with," from assimilated form of com "with" (see com-) + laborare "to work" (see labor (v.)).

In a bad sense, "traitorous cooperation with an occupying enemy," it is recorded from 1940; earliest references are to the Vichy Government of France. Collaborationist was used disparagingly in socialist jargon from 1922.

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