Care for teacher is head's part (7)
I believe the answer is:
cherish
'care for' is the definition.
(synonyms)
'teacher is head's part' is the wordplay.
'teacher' becomes 'cher' (I can't explain this - if you can you should give a lot more credence to this answer).
'part' says to take the initial letters.
The initial letter of 'heads' is 'h'.
'cher'+'is'+'h'='CHERISH'
Can you help me to learn more?
(Other definitions for cherish that I've seen before include "Hold dear, value greatly" , "Love" , "Hold dear, keep in one's heart" , "Hold dear, treasure" , "Nurture (a hope)" .)