Leave an Adriatic resort (5)
I believe the answer is:
split
This clue is a double definition.
'leave' is the first definition.
(I've seen this before)
'adriatic resort' is the second definition.
(Croatian city)
'an' acts as a link.
(Other definitions for split that I've seen before include "ice cream concoction" , "Cause fission of (atom)" , "Break; fissure" , "Cut, cleft" , "Rent" .)