Sum put away in stricken desperation when half of earnings are stolen (7)
I believe the answer is:
deposit
'sum' is the definition.
(I have seen 'Returnable sum' mean 'deposit' so perhaps 'sum' could also mean 'deposit')
'put away in stricken desperation when half of earnings are stolen' is the wordplay.
I cannot really see how this works, but
'put' could be 'posit' (positing is a kind of putting) and 'posit' is present in the answer.
'when' could be 'e' (I've seen this in other clues) and 'e' is located in the answer.
A single letter 'd' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for deposit that I've seen before include "Precipitate" , "I posted (anag.)" , "Down-payment" , "Set down" , "Sum of money paid into a bank account" .)