Levy one penny in some confusion (6)
I believe the answer is:
impose
'levy' is the definition.
(I know that levy can be written as impose)
'one penny in some confusion' is the wordplay.
'one' becomes 'I' (Roman numeral).
'penny' becomes 'p' (short for pence).
'in' is an insertion indicator.
'confusion' indicates an anagram.
'some' anagrammed gives 'mose'.
'p' placed within 'mose' is 'mpose'.
'i'+'mpose'='IMPOSE'
(Other definitions for impose that I've seen before include "Force (on someone)" , "Put or lay on- say a tax" , "Exact or levy, say tax" , "As task, set" , "Force (something) to be done or accepted" .)