Charge leader of forty Europeans
I believe the answer is:
fee
'charge' is the definition.
(I know that fee is a type of fixed charge)
'leader of forty europeans' is the wordplay.
'leader of' suggests taking the first letters.
'europeans' becomes 'ee' (I've seen this in other clues).
The initial letter of 'forty' is 'f'.
'f'+'ee'='FEE'
(Other definitions for fee that I've seen before include "Sum payable to professional person for services" , "(Entry) charge" , "Amount paid for job" , "Money paid for professional services" , "Sum payable to, say, barrister" .)