Bedtime drink that may go to your head? (8)
I believe the answer is:
nightcap
'bedtime drink that may go to your head?' is the definition.
'nightcap' can be an answer for 'bedtime drink' (I've seen this before). I am not certain of the remainder of the definition.
'bedtime drink that may go to your head?' is the wordplay.
I cannot quite understand how this works, but
'bedtime' could be 'night' and 'night' is located in the answer.
'head?' could be 'cap' (both can mean the top of something) and 'cap' is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for nightcap that I've seen before include "Bedtime beverage" , "attire" , "Patching up with drink at bedtime" , "A drink before sleep" , "A drink before bed, wearing nocturnal headgear" .)