Being alcoholic, it detracts from alertness (3)
I believe the answer is:
ale
This might be a double definition.
'being alcoholic' is the first definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'it detracts from alertness' is the second definition.
The definition suggests a singular noun which matches the answer.
Can you help me to learn more?
(Other definitions for ale that I've seen before include "festival" , "Beer consumed in sales" , "Similar to beer" , "Booze" , "English beer, mild or bitter" .)