Silly wind-up does upset (6,4)
I believe the answer is:
upside down
'upset' is the definition.
(thesaurus)
'silly wind-up does' is the wordplay.
'silly' indicates anagramming the letters.
'wind'+'up'+'does'='windupdoes'
'windupdoes' is an anagram of 'UPSIDE-DOWN'.
(Other definitions for upside down that I've seen before include "kind of cake" , "at sixes and sevens" , "The wrong way up" , "in a crazy way" , "in disarray" .)