Intoxicated guard giving up a hallucinogenic substance (4)
I believe the answer is:
drug
'hallucinogenic substance' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'intoxicated guard giving up a' is the wordplay.
'intoxicated' indicates an anagram.
'giving up' indicates named letters should be taken away.
'guard' with 'a' taken out is 'gurd'.
'gurd' anagrammed gives 'DRUG'.
Can you help me to learn more?
(Other definitions for drug that I've seen before include "Medication" , "Medical or narcotic substance" , "Pharmaceutical (or recreational) item" , "Chemical medicament" , "LSD, say" .)