Gone astray 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 astray near a' is the wordplay.
'astray' indicates an anagram.
'near' means one lot of letters go next to another.
'gone' is an anagram of 'geno'.
'geno'+'a'='GENOA'
(Other definitions for genoa that I've seen before include "Italian city; sail" , "Seaport in northwestern Italy" , "City of Italy" , "Cake type; foresail" , "North Italian port" .)