Drunk bachelor seen before game of chance (6)
I believe the answer is:
blotto
'drunk' is the definition.
(slang term)
'bachelor seen before game of chance' is the wordplay.
'bachelor' becomes 'B' (abbreviation e.g. BA=Bachelor of Arts).
'seen before' means one lot of letters go next to another.
'game of chance' becomes 'lotto' (I've seen this before).
'b'+'lotto'='BLOTTO'
(Other definitions for blotto that I've seen before include "Helplessly drunk (slang)" , "Boot Lt. out for being drunk" , "Very drunk (informal)" , "As one plastered" , "Stoned" .)