Nuts are not elaborately decorated (6)
I believe the answer is:
ornate
'elaborately decorated' is the definition.
(I've seen this before)
'nuts are not' is the wordplay.
'nuts' indicates anagramming the letters (nuts can mean crazy).
'are'+'not'='arenot'
'arenot' with letters rearranged gives 'ORNATE'.
(Other definitions for ornate that I've seen before include "Richly decorated, perhaps too much so" , "Elaborately decorated, perhaps overdone" , "Ostentatious" , "Florid" , "Baroque" .)