Guided bull with keys (7)
I believe the answer is:
steered
'guided' is the definition.
('steer' can be a synonym of 'guide')
'bull with keys' is the wordplay.
I cannot quite understand how this works, but
'bull' could be 'steer' (I've seen this before) and 'steer' is present in the answer.
The remaining letters 'ed' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for steered that I've seen before include "given the push" , "Guided a vehicle" , "Went on a course" , "taken the helm" , "Guided or directed, ship or plane" .)