Indy entrant (5)
I believe the answer is:
racer
'indy entrant' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for racer that I've seen before include "Fast mover" , "Athlete" , "Participant in speed contest" , "Fast-moving animal" , "Perhaps 16 [SCRAMBLER]" .)