Nuisance admits a lack of energy at school producing reused manuscript (10)
I believe the answer is:
palimpsest
'manuscript' is the definition.
(palimpsest is a kind of manuscript)
'nuisance admits a lack of energy at school' is the wordplay.
'nuisance' becomes 'pest' (I've seen this before).
'admits' means one lot of letters goes inside another.
'lack of energy at' becomes 'limp' (I can't explain this - if you can you should give a lot more credence to this answer).
'school' becomes 's'.
'a'+'limp'+'s'='alimps'
'pest' placed around 'alimps' is 'PALIMPSEST'.
'producing reused' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for palimpsest that I've seen before include "Simple taps (anag.); a manuscript" , "recycled document" , "Recycled manuscript" , "Reused parchment" .)