Gone swimming near a port in Italy (5)
I believe the answer is:
genoa
'port in italy' is the definition.
(I've seen this in another clue)
'gone swimming near a' is the wordplay.
'swimming' indicates an anagram.
'near' is a charade indicator (letters next to each other).
'gone' with letters rearranged gives 'geno'.
'geno'+'a'='GENOA'
(Other definitions for genoa that I've seen before include "North Italian port" , "Type of rich fruit cake" , "Seaport in northwestern Italy" , "City of Italy" , "Italian city; sail" .)