Determined Spooner's supposed amount owed (4,3)
I believe the answer is:
dead set
'determined' is the definition.
(I've seen this in another clue)
'spooner's supposed amount owed' is the wordplay.
I cannot really understand how this works, but
'amount' could be 'set' (set is a kind of amount) and 'set' is found within the answer.
The remaining letters 'dead' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for dead set that I've seen before include "Bent on - sedated (anag)" , "Absolutely - sedated (anag)" , "A determined attack - from extinct group?" , "Absolutely determined, bent on" , "Fully determined" .)