Guide a bullock (5)
I believe the answer is:
This clue is a double definition.
'guide' is the first definition.
'a bullock' is the second definition.
('steer' can be a synonym of 'bullock')
(Other definitions for steer that I've seen before include "cow!" , "piece of advice" , "Direct; young ox" , "Direct, fix course" , "Con" .)