Whizz in Rolls-Royce for fast driver (5)
I believe the answer is:
racer
'fast driver' is the definition.
(I've seen this before)
'whizz in rolls-royce' is the wordplay.
'whizz' becomes 'ace' (synonyms).
'in' means one lot of letters goes inside another.
'rolls royce' becomes 'rr' (short for Rolls Royce).
'ace' put inside 'rr' is 'RACER'.
'for' acts as a link.
(Other definitions for racer that I've seen before include "Participant in speed contest" , "Fast competitive car or animal" , "Speedway competitor, perhaps" , "one in a hurry" , "Fast mover" .)