Post agreement (14)

I believe the answer is:

correspondence

I believe this clue is a double definition.

'post' is the first definition.
(I've seen this before)

'agreement' is the second definition.
('correspondence' can be a synonym of 'agreement')

(Other definitions for correspondence that I've seen before include "written communication" , "Letters sent or received" , "close similarity" , "Letters, etc" , "agreement" .)

I've seen this clue in The Telegraph.

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