Former pupil leaves opposing element of literary theme (5)
I believe the answer is:
verse
'former pupil' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'opposing element of literary theme' is the wordplay.
'opposing' becomes 'v' (abbreviation for versus).
'element of literary theme' becomes 'erse' (I can't explain this - if you can you should believe this answer much more).
'v'+'erse'='VERSE'
'leaves' is the link.
Can you help me to learn more?
(Other definitions for verse that I've seen before include "Literature in metrical form" , "Section of a poem" , "Part of a song or poem" , "Poems" , "Poetry - subdivision of the Bible" .)