Some drinking Dan's knockout port (6)
I believe the answer is:
gdansk
'port' is the definition.
(port in Poland)
'some drinking dan's knockout' is the wordplay.
'some' indicates a hidden word (some parts of the word are used).
'GDANSK' can be found hidden inside 'drinking dans knockout'.
(Other definitions for gdansk that I've seen before include "Polish seaport" , "Polish city on the Baltic" , "It was once called Danzig" , "Port city of Poland" , "Major Polish port" .)