Guide bullock (5)
I believe the answer is:
steer
I believe this is a double definition.
'guide' is the first definition.
(I know that guide can be written as steer)
'bullock' is the second definition.
(I know that bullock can be written as steer)
(Other definitions for steer that I've seen before include "Exercise control" , "Guide (a ship, car, etc)" , "Cattle - drive" , "Guide, direct" , "Direct movement" .)