It's best to give work to head teacher, though first person is expressing hesitation, perhaps (7)
I believe the answer is:
optimum
'it's best' is the definition.
(optimum means the best possible)
'work to head teacher though first person is expressing hesitation perhaps' is the wordplay.
I cannot quite understand how this works, but
'work' could be 'op' (abbreviation for opus) and 'op' is present in the answer.
'first' could be 'i' (I in Roman numerals eg Elizabeth I) and 'i' is located in the answer.
'hesitation' could be 'um' (sound made when hesitating) and 'um' is present in the answer.
This explanation may well be incorrect...
'to give' is the link.
Can you help me to learn more?
(Other definitions for optimum that I've seen before include "Most favourable (conditions)" , "Best, most favourable" , "Most favourable amount" , "Most favourable point" , "top condition" .)