Studied bundle that's turned up prior to lecture (9)
I believe the answer is:
elaborate
'studied' is the definition.
(thesaurus)
'bundle that's turned up prior to lecture' is the wordplay.
'bundle' becomes 'bale' (bale is a kind of bundle).
'that's turned up' is a reversal indicator (in a down clue, letters go up).
'prior to' means one lot of letters go next to another.
'lecture' becomes 'orate' (I've seen this in another clue).
'bale' back-to-front is 'elab'.
'elab'+'orate'='ELABORATE'
(Other definitions for elaborate that I've seen before include "Give more details" , "Highly detailed" , "Complicate" , "Complicated - work out" , "Expand (upon)" .)