Driver's woe
I believe the answer is:
flat
'driver's woe' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for flat that I've seen before include "Quarters - punctured - smooth" , "one or more in uniform" , "Pied-a-terre" , "Level - below the natural note" , "Prostrate" .)