Money we kept back to get nut (6)
I believe the answer is:
cashew
'nut' is the definition.
(I know that cashew is a type of nut)
'money we kept back' is the wordplay.
'money' becomes 'cash' (cash is a type of money).
'kept back' says the letters should be written backwards.
'we' in reverse letter order is 'ew'.
'cash'+'ew'='CASHEW'
'to get' is the link.
(Other definitions for cashew that I've seen before include "snack perhaps" , "Acajou" , "Kidney-shaped nut of tropical tree" , "Chew as you would this nut" , "Kidney shaped nut" .)