Near agreement about drink before retiring (8)
I believe the answer is:
nightcap
'drink before retiring' is the definition.
I can't tell whether this definition defines the answer.
'near agreement about' is the wordplay.
'near' becomes 'nigh' (similar in meaning).
'agreement' becomes 'pact' (a pact is an agreement or deal).
'about' says the letters should be written backwards.
'pact' in reverse letter order is 'tcap'.
'nigh'+'tcap'='NIGHTCAP'
Can you help me to learn more?
(Other definitions for nightcap that I've seen before include "late evening beverage" , "drink having sleepy effect?" , "A drink before bed, probably alcoholic" , "what last drink might be" , "Tot, at bedtime" .)