Walkway by the sea (9)
I believe the answer is:
esplanade
'walkway by the sea' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for esplanade that I've seen before include "Seafront walk" , "Seaside resort walk" , "Long wide pavement next to a beach" , "Promenade" , "Open, level space for walks or drives" .)