But for being unique (4)

I believe the answer is:

only

I believe this clue is a double definition.

'but' is the first definition.
(I've seen this in another clue)

'unique' is the second definition.
(synonyms)

'for being' acts as a link.

(Other definitions for only that I've seen before include "Simply" , "Exclusive - individual" , "And nothing more; sole" , "Unique; merely" , "See 6" .)

I've seen this clue in the Evening Standard.

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