Dean spilt port (4)
I believe the answer is:
aden
'port' is the definition.
(I've seen this before)
'dean spilt' is the wordplay.
'spilt' indicates an anagram.
'dean' is an anagram of 'ADEN'.
(Other definitions for aden that I've seen before include "Red Sea port" , "Former Br. Gulf colony" , "Yemeni port" , "Port city of Yemen" , "Dean is in the Yemen, strangely" .)