Being a slipper, it has no wheels! (4)
I believe the answer is:
sled
'being' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for sled that I've seen before include "Sledge" , "Snow vehicle" , "Winter transport" , "Tray on which to slide" , "Snow transport" .)