Road hog? (6)
I believe the answer is:
harley
'road hog?' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for harley that I've seen before include "London thoroughfare famed for doctors" , "London street noted for top doctors" , "-- Street, London centre for doctors" , "This London street is famous for top doctors" , "London street famed for expensive doctors" .)