One's chased fancy car through waterfront area (6)
I believe the answer is:
quarry
'one's chased' is the definition.
(an animal's prey or quarry)
'fancy car through waterfront area' is the wordplay.
'fancy car' becomes 'RR' (Rolls Royce).
'through' indicates putting letters inside (inserted letters go through the word).
'waterfront area' becomes 'quay' (platform by the sea).
'rr' going inside 'quay' is 'QUARRY'.
(Other definitions for quarry that I've seen before include "Source of stone" , "Animal caught" , "what one seeks ..." , "Excavation for extracting stone or slate" , "Prey or stone pit" .)