To some extent, teacher is hard to hold dear (7)
I believe the answer is:
cherish
'hold dear' is the definition.
('cherish' can be a synonym of 'hold dear')
'to some extent teacher is hard' is the wordplay.
'to some extent' indicates a hidden word.
'CHERISH' can be found hidden inside 'teacher is hard'.
'to' is the link.
(Other definitions for cherish that I've seen before include "Hold dear, be fond of" , "Nurse" , "Nurture (a hope)" , "Foster" , "Hold dear, value greatly" .)