Be taken aback during date's lively discussion (6)
I believe the answer is:
debate
'lively discussion' is the definition.
'debate' can be an answer for 'discussion' (debate is a kind of discussion). I am not sure about the 'lively' bit.
'be taken aback during date's' is the wordplay.
'taken aback' says the letters should be written backwards.
'during' means one lot of letters goes inside another.
'be' in reverse letter order is 'eb'.
'eb' inserted within 'date' is 'DEBATE'.
Can you help me to learn more?
(Other definitions for debate that I've seen before include "Discussion throung argument" , "Discuss (in parliament)" , "consideration" , "Formal public discussion" , "Ponder" .)