Disheartened teacher, taking the head off child in ancient battle site (4)
I believe the answer is:
troy
'ancient battle site' is the definition.
(I've seen this in another clue)
'disheartened teacher taking the head off child' is the wordplay.
'disheartened' means to remove the middle letters (the middle or heart is removed).
'taking' is a charade indicator (letters next to each other).
'the head off child' becomes 'oy' (I can't explain this - if you can you should believe this answer much more).
'teacher' with its centre taken out is 'tr'.
'tr'+'oy'='TROY'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for troy that I've seen before include "City besieged by the Greeks - system of weights for gems" , "Ancient beseiged city" , "System of weights for precious stones and metals" , "Ancient city besieged to free beautiful Helen" , "City besieged by Greeks to rescue Helen" .)