Airman destroyed harbour (6)
I believe the answer is:
marina
'harbour' is the definition.
(marina is a type of harbour)
'airman destroyed' is the wordplay.
'destroyed' indicates an anagram.
'airman' anagrammed gives 'MARINA'.
(Other definitions for marina that I've seen before include "Airman (anag)" , "part of harbour?" , "Base for pleasure boats" , "Yachting centre" , "Docking facility for pleasure craft" .)