Large amount of money in substantial property (4)
I believe the answer is:
pile
This clue could be a double definition.
'large amount of money' is the first definition.
(I've seen this in another clue)
'substantial property' is the second definition.
'pile' can be an answer for 'property' (pile is a kind of property). I'm unsure of the 'substantial' bit.
'in' is the link.
Can you help me to learn more?
(Other definitions for pile that I've seen before include "A heap or stack" , "Part of reactor" , "lot of money" , "large amount of money" , "Fortune" .)