Cove hidden by beach — a pity (4)
I believe the answer is:
'cove' is the definition.
'hidden by beach a pity' is the wordplay.
'hidden' indicates the answer is hidden within the clue.
'CHAP' is hidden within 'by beach a pity'.
(Other definitions for chap that I've seen before include "Sore; cheek; man" , "Fellow < makes > crack" , "we prefer not to have on hand" , "Fellow; sore skin area" , "Become sore; fellow" .)