Racing toboggan (4)
I believe the answer is:
luge
'racing toboggan' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for luge that I've seen before include "Glue for a one-man sledge" , "Small sleigh" , "Racing sled for one or two people" , "Form of toboggan" , "Glue (anag) - racing toboggan" .)