Moved smoothly along a surface (4)
I believe the answer is:
slid
'moved smoothly along a surface' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for slid that I've seen before include "Skidded, slewed" , "Moved (eg, on ice)" , "Moved smoothly along a surface" , "Slipped" .)