Fancy 'ooter polished off (6)
I believe the answer is:
ornate
'fancy' is the definition.
(I've seen this before)
''ooter polished off' is the wordplay.
''ooter' becomes ''orn' ('horn' - instrument making a hooting sound - said with a cockney accent, dropping the 'H', like 'hooter' was).
'polished off' becomes 'ate' (I've seen this in another clue).
'orn'+'ate'='ORNATE'
(Other definitions for ornate that I've seen before include "Richly adorned and elaborate" , "Fancy" , "Over-elaborate" , "Florid" , "Detailed" .)