Harbour with own pole (5)
I believe the answer is:
haven
'harbour' is the definition.
(I know that harbour can be written as haven)
'with own pole' is the wordplay.
'with' means one lot of letters go next to another.
'own' becomes 'have' (synonyms).
'pole' becomes 'n' (abbreviation for North, as in North Pole).
'have' put next to 'n' is 'HAVEN'.
(Other definitions for haven that I've seen before include "Refuge; harbour" , "Sheltered port" , "Anchorage - retreat" , "Safe port" , "Shelter (for ships)" .)