Overcharge individual involved in special free port (9)
I believe the answer is:
profiteer
'overcharge' is the definition.
(I've seen this before)
'individual involved in special free port' is the wordplay.
'individual' becomes 'i' (Roman numeral for one).
'involved in' is an insertion indicator.
'special' indicates an anagram.
'free'+'port'='freeport'
'freeport' anagrammed gives 'profteer'.
'i' put inside 'profteer' is 'PROFITEER'.
(Other definitions for profiteer that I've seen before include "He charges too much in times of scarcity" , "Racketeer" , "Make excessive gains" , "Make money unfairly" , "capitalist" .)