Opposes further exams head of school's introduced (7)
I believe the answer is:
resists
'opposes further' is the definition.
'resists' can be an answer for 'opposes' (resisting is a kind of opposing). I'm not certain of the 'further' bit.
'exams head of school's introduced' is the wordplay.
'exams' becomes 'resits' (I have seen 'second exams' mean 'resits' so perhaps 'exams' could also mean 'resits').
'head of' says to take the initial letters.
'introduced' indicates putting letters inside.
The first letter of 'schools' is 's'.
'resits' placed around 's' is 'RESISTS'.
Can you help me to learn more?
(Other definitions for resists that I've seen before include "Fights back" , "Is reluctant" , "Tries to stop" , "Sisters (anag.)" , "Struggles against" .)