It may be worn as a favour (7)

I believe the answer is:

rosette

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'a favour' is the definition.
('favour' historically meant a token of affection)

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for rosette that I've seen before include "Political supporter's ribbon" , "sign of support for party" , "Ribboned decoration" , "Ribboned award" , "decoration showing support for party" .)

I've seen this clue in The Globe and Mail.

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