Mum's eaten stewed game? (9)
I believe the answer is:
amusement
'game?' is the definition.
(thesaurus)
'mum's eaten stewed' is the wordplay.
'stewed' indicates anagramming the letters.
'mums'+'eaten'='mumseaten'
'mumseaten' anagrammed gives 'AMUSEMENT'.
(Other definitions for amusement that I've seen before include "Light-hearted pastime" , "Something which entertains" , "(State of) finding something funny" , "Pleasure, diversion" , "set up through arcade?" .)