Road furrow (3)
I believe the answer is:
rut
'road furrow' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rut that I've seen before include "Deep track or dull routine" , "It's hard to get out of" , "Groove worn by wheels" , "Groove made by wheel" , "Groove worn in surface" .)