Expression of a former country's disorder (6)

I believe the answer is:

chorea

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'disorder' is the definition.
(chorea is a kind of disorder)

I cannot understand how the rest of the clue works.

(Other definitions for chorea that I've seen before include "Nervous condition, often with facial twitching" , "nervous disorder" , "Huntington's --, nervous condition" , "Neurological disorder" .)

I've seen this clue in The Times.

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