Bounder gets foolish knocking back port (9)

I believe the answer is:

rotterdam

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'port' is the definition.
(I know that Rotterdam is a port)

'bounder gets foolish knocking back' is the wordplay.
'bounder' becomes 'rotter' (I've seen this before).
'gets' is a charade indicator (letters next to each other).
'foolish knocking back' becomes 'dam' (I can't justify this - if you can you should believe this answer much more).
'rotter'+'dam'='ROTTERDAM'

Can you help me to learn more?

(Other definitions for rotterdam that I've seen before include "European city" , "Dutch city and port" , "Netherlands port" , "European port" , "city abroad" .)

I've seen this clue in The Sunday Times and The Times.

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