Sorry guys dropping odds for bacchanalia (4)
I believe the answer is:
orgy
'for bacchanalia' is the definition.
(synonyms)
'sorry guys dropping odds' is the wordplay.
'dropping odds' indicates alternate letters (the odd-numbered letters are removed).
'sorry'+'guys'='sorryguys'
The alternate letters of 'sorryguys' are 'ORGY'.
(Other definitions for orgy that I've seen before include "wild spree" , "riot" , "A licentious immoral party" , "Excess" , "Unrestrained revel" .)