Swine crazy about Dutch port (9)
I believe the answer is:
rotterdam
'dutch port' is the definition.
(I know that Rotterdam is a port settlement)
'swine crazy about' is the wordplay.
'swine' becomes 'rotter'.
'crazy' becomes 'mad' (synonyms).
'about' says the letters should be written backwards.
'mad' reversed gives 'dam'.
'rotter'+'dam'='ROTTERDAM'
(Other definitions for rotterdam that I've seen before include "city abroad" , "Netherlands port" , "Major world seaport at the mouth of the Meuse" , "European port" , "One of the world's largest ports" .)