Fancy headgear Eric exchanged (7)
I believe the answer is:
caprice
'fancy' is the definition.
(thesaurus)
'headgear eric exchanged' is the wordplay.
'headgear' becomes 'cap' (cap is a kind of headgear).
'exchanged' is an anagram indicator.
'eric' anagrammed gives 'rice'.
'cap'+'rice'='CAPRICE'
(Other definitions for caprice that I've seen before include "Sudden impulse" , "Sudden mood change" , "Sudden change of mind" , "A whim, or piece of music in lively fanciful style" , "unaccountable change" .)