A neurotic drunk - on this? (9)
I believe the answer is:
cointreau
'this?' is the definition.
The definition suggests a singular noun which matches the answer.
'a neurotic drunk on' is the wordplay.
'drunk' is an anagram indicator.
'on' is an insertion indicator (as in clothing 'on' a person).
'neurotic' is an anagram of 'cointreu'.
'a' placed inside 'cointreu' is 'COINTREAU'.
Can you help me to learn more?
(Other definitions for cointreau that I've seen before include "Alcoholic drink" , "A sweet orange-flavoured liqueur for cautioner" , "Orange liqueur" , "Sweet orange-flavoured colourless liqueur" .)