Share Jill Masterson's fate, and it's goodbye! (5)

I believe the answer is:

adieu

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'it's goodbye' is the definition.
(synonyms)

I don't understand the remainder of the clue.

(Other definitions for adieu that I've seen before include "So long abroad" , "12 Down" , "Farewell to France" , "All the best" , "Goodbye, mon ami!" .)

I've seen this clue in The Telegraph.

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