On a bender it turned out, one's drunk (10)
I believe the answer is:
inebriated
'drunk' is the definition.
(inebriating is a kind of drinking)
'on a bender it turned out one's' is the wordplay.
'on' says to put letters next to each other.
'turned out' is an anagram indicator.
'one' becomes 'i' (Roman numeral).
'a'+'bender'+'it'='abenderit'
'abenderit' with letters rearranged gives 'nebriated'.
'nebriated' after 'i' is 'INEBRIATED'.
(Other definitions for inebriated that I've seen before include "Tipsy" , "wasted" , "Bombed" , "Drunk" .)