Top cut off money tree (3)
I believe the answer is:
ash
'tree' is the definition.
(ash is a kind of tree)
'top cut off money' is the wordplay.
'top cut off' means to remove the first letter.
'money' becomes 'cash' (cash is a type of money).
'cash' with its first letter removed is 'ASH'.
(Other definitions for ash that I've seen before include "Timber tree" , "Hard pale wood" , "In fireplace it may be" , "Fraxinus" , "Burnt remains; tree" .)