The loaf to use sensibly (4)
I believe the answer is:
head
'the loaf' is the definition.
(I've seen this in other clues)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for head that I've seen before include "bean" , "John on board" , "Source of river, leader" , "Skull" , "Person in charge" .)