Traction aid (5)
I believe the answer is:
cleat
'traction aid' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for cleat that I've seen before include "Support" , "Strip used to strengthen a surface to which it is attached" , "Device on which to secure a rope" , "Projection for a rope on board" , "Projection for a rope on a boat" .)