Poetry of the silver sea (5)
I believe the answer is:
verse
'poetry' is the definition.
(synonyms)
'of the silver sea' is the wordplay.
'of' says the answer is hidden in the clue.
'VERSE' is hidden in the letters of 'silver sea'.
(Other definitions for verse that I've seen before include "few lines of writing?" , "Part of a song or poem" , "Part of hymn" , "literary offering" , "Section of a poem" .)