Write revolutionary melody for trident carrier (7)
I believe the answer is:
neptune
'trident carrier' is the definition.
(I've seen this in another clue)
'write revolutionary melody' is the wordplay.
'write' becomes 'pen' (synonyms).
'revolutionary' is a reversal indicator (letters revolve around).
'melody' becomes 'tune' (synonyms).
'pen' reversed gives 'nep'.
'nep'+'tune'='NEPTUNE'
'for' acts as a link.
(Other definitions for neptune that I've seen before include "in Holst's suite" , "Roman sea-god" , "Roman god of water and the sea" , "Roman sea god - planet" , "extract from The Planets" .)