Heads giving former pupil some poetry (7)
I believe the answer is:
obverse
'heads' is the definition.
(I've seen this before)
'giving former pupil some poetry' is the wordplay.
'giving' is a charade indicator (letters next to each other).
'former pupil' becomes 'OB' (abbreviation for 'Old Boy').
'some poetry' becomes 'verse' (synonyms).
'ob'+'verse' is 'OBVERSE'.
(Other definitions for obverse that I've seen before include "Being opposite in verbose way" , "monarch's head here" , "Side of a coin that shows the head" , "Verbose about coin side" , "Coin's head side" .)