Embark on wild binge (5)
I believe the answer is:
begin
'embark on' is the definition.
(synonyms)
'wild binge' is the wordplay.
'wild' indicates an anagram.
'binge' is an anagram of 'BEGIN'.
(Other definitions for begin that I've seen before include "Monachem --" , "Commence" , "Partly open" , "Initiate" , "Israeli statesman" .)