The greatest circulators of banknotes will do so (9)
I believe the answer is:
uttermost
'the greatest' is the definition.
(I've seen this before)
'circulators of banknotes will do so' is the wordplay.
I cannot really understand how this works, but
'of' could be 'o' and 'o' is located in the answer.
'do' could be 'ut' (synonyms) and 'ut' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for uttermost that I've seen before include "best" , "The furthest point or degree" , "Chief" , "Extreme" , "at the furthest limit" .)