Completely unlocked? (4)
I believe the answer is:
bald
'unlocked?' is the definition.
(having no locks of hair)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for bald that I've seen before include "Without the natural covering" , "Not covered with hair" , "Lacking hair on the head" , "Unadorned" , "With the tread worn away" .)