Go downhill fast (3)
I believe the answer is:
ski
This could be a double definition.
'go' is the first definition.
(skiing is a kind of going)
'downhill fast' is the second definition.
I know that 'downhill' relates to this answer. I also know that both the answer and definition are singular nouns
Can you help me to learn more?
(Other definitions for ski that I've seen before include "Type of snow shoe" , "Runner for use on snow" , "Alpine runner" , "Winter sports equipment" , "Engage in a winter sport" .)