Fight expected against school's closure (4)
I believe the answer is:
duel
'fight' is the definition.
(I know that duel is a type of fight)
'expected against school's closure' is the wordplay.
'expected' becomes 'due' (similar in meaning).
'against' is a charade indicator (letters next to each other).
'closure' indicates one should take the final letters (the letter which closes the word).
The last letter of 'school' is 'l'.
'due'+'l'='DUEL'
(Other definitions for duel that I've seen before include "Potentially fatal fight between two people" , "Prearranged fight with deadly weapons between two people" , "Contest between two with deadly weapons" , "Two-person combat" , "Combat between two people in matter of honour" .)