One may go downhill fast (5)
I believe the answer is:
skier
This clue could be a double definition.
'one may go downhill' is the first definition.
(I've seen this in another clue)
'fast' is the second definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
Can you help me to learn more?
(Other definitions for skier that I've seen before include "One up mountain, perhaps" , "One on the piste" , "Winter sportsman" , "Winter sports person" , "He glides over snow, perhaps in sport" .)