… from wrong case of champagne (5)
I believe the answer is:
since
'from' is the definition.
(I've seen this in another clue)
'wrong case of champagne' is the wordplay.
'wrong' becomes 'sin' (wrong can mean a sin or crime).
'case of' means to remove the middle letters (like emptying a case).
'champagne' with its middle removed is 'ce'.
'sin'+'ce'='SINCE'
(Other definitions for since that I've seen before include "in the past" , "Seeing that" , "Because; ago" , "From that time one" .)