Inebriate duke, after dash in dark, collapsed (8)
I believe the answer is:
drunkard
'inebriate' is the definition.
(I know that inebriate can be written as drunkard)
'duke after dash in dark collapsed' is the wordplay.
'duke' becomes 'd' (abbreviation).
'after' is a charade indicator (letters next to each other).
'dash' becomes 'run' (I've seen this before).
'in' indicates putting letters inside.
'collapsed' is an anagram indicator.
'dark' is an anagram of 'kard'.
'run' inserted into 'kard' is 'runkard'.
'd'+'runkard'='DRUNKARD'
(Other definitions for drunkard that I've seen before include "One gets soaked" , "Alcoholic" , "alkie" , "boozer" , "Sot, addicted drinker" .)