Money boxes at centre of big game (8)
I believe the answer is:
patience
'game' is the definition.
(I know that patience is a type of card game)
'money boxes at centre of big' is the wordplay.
'money' becomes 'pence' (I've seen this before).
'boxes' means one lot of letters goes inside another (the outside letters must 'box' inside letters in).
'centre of' means to look at the middle letters.
The centre of 'big' is 'i'.
'at'+'i'='ati'
'pence' enclosing 'ati' is 'PATIENCE'.
(Other definitions for patience that I've seen before include "Composure" , "that one plays" , "G & S' alternative for "Bunthorne''s Bride"" , "Forbearance and long-suffering" , "Card came for one" .)