Principal traitors stand up (4)

I believe the answer is:

star

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'principal' is the definition.
('star' can be a synonym of 'principal')

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for star that I've seen before include "Symbol of excellence" , "virtuoso" , "Play a leading role" , "feature in film" , "Asterisk" .)

I've seen this clue in The Independent.

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