Soon to be unknown (4)

I believe the answer is:

anon

I believe this is a double definition.

'soon' is the first definition.
(synonyms)

'be unknown' is the second definition.
(I've seen this before)

'to' acts as a link.

(Other definitions for anon that I've seen before include "Some time soon" , "Soon or presently" , "Writer unknown" , "Presently - unattributed" , "Of unknown name (abbr)" .)

I've seen this clue in the Evening Standard and The Everyman puzzle in The Observer.

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