Fat chanteuse returned cases (4)
I believe the answer is:
suet
'fat' is the definition.
(suet is a kind of fat)
'chanteuse returned cases' is the wordplay.
'cases' indicates a hidden word.
'returned' says the letters should be written in reverse.
'teus' can be found hidden inside 'chanteuse'.
'teus' back-to-front is 'SUET'.
(Other definitions for suet that I've seen before include "Hard fat from beef and sheep" , "Fat used in foods" , "Solid fat used in cooking" , "Fatty tissue" , "Thin pancake" .)