Unable to open up to couple losing the head with local drunk (8)
I believe the answer is:
airtight
'up to couple losing the head with local drunk' is the definition.
I can't judge whether this definition defines the answer.
'unable to open' is the wordplay.
'unable' becomes 'tight' (I can't justify this - if you can you should give a lot more credence to this answer).
'to' says to put letters next to each other (I've seen this in other clues).
'open' becomes 'air' (synonyms).
'tight' after 'air' is 'AIRTIGHT'.
Can you help me to learn more?
(Other definitions for airtight that I've seen before include "Not allowing gas to pass" , "securely sealed" , "Without weak points" , "With no opening" , "Firmly closed" .)