Monarch's coin (9)

I believe the answer is:

sovereign

This clue is a double definition.

'monarch's' is the first definition.
(synonyms)

'coin' is the second definition.
(thesaurus)

(Other definitions for sovereign that I've seen before include "Supreme ruler" , "Old gold coin" , "Ruler - gold coin" , "Head of state" , "Her Maj?" .)

I've seen this clue in The Daily Express.

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