What a stubborn fellow still won't do (5)
I believe the answer is:
budge
'do' is the definition.
The answer and definition can be both to do with motion as well as being verbs in their base form.
Perhaps there's a link between them I don't understand?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for budge that I've seen before include "Stiff" , "Make the slightest movement" , "Pompous" , "Move slightly - perhaps in opinion" , "Cause to alter an opinion or stance, shift" .)