Pack up before lecture becomes complicated (9)
I believe the answer is:
elaborate
'complicated' is the definition.
(I've seen this before)
'pack up before lecture' is the wordplay.
'pack' becomes 'bale' (I can't justify this - if you can you should give a lot more credence to this answer).
'up' is a reversal indicator (in down clue: letters go upwards).
'before' says to put letters next to each other.
'lecture' becomes 'orate' (I've seen this before).
'bale' in reverse letter order is 'elab'.
'elab'+'orate'='ELABORATE'
'becomes' is the link.
Can you help me to learn more?
(Other definitions for elaborate that I've seen before include "Fussy" , "Extravagant" , "Detailed, complicated" , "Complicate" , "Work out or describe in detail" .)