Person using a starting block (5)
I believe the answer is:
racer
(Other definitions for racer that I've seen before include "Fast driver" , "fast-moving vehicle" , "sportsman" , "Fast-moving animal" , "Fast competitive car or animal" .)
I believe the answer is:
racer
(Other definitions for racer that I've seen before include "Fast driver" , "fast-moving vehicle" , "sportsman" , "Fast-moving animal" , "Fast competitive car or animal" .)