Sloping walkway (4)
I believe the answer is:
ramp
'sloping walkway' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ramp that I've seen before include "Something that's not on the level" , "Short slope" , "One with an inclination" , "Sloping platform" , "Inclined path" .)