Busy men with a net at sea (6)
I believe the answer is:
ornate
'busy' is the definition.
(I've seen this in another clue)
'men with a net at sea' is the wordplay.
'men' becomes 'or' (military abbreviation for other ranks).
'with' means one lot of letters goes inside another.
'at sea' indicates an anagram.
'net' anagrammed gives 'nte'.
'a' placed into 'nte' is 'nate'.
'or'+'nate'='ORNATE'
(Other definitions for ornate that I've seen before include "Richly decorative" , "(Of literary style) complex and with unusual words" , "Highly decorative" , "Elaborate, flowery" , "Richly decorated, perhaps too much so" .)