Drunk on music? It's impenetrable (8)
I believe the answer is:
airtight
This might be a double definition.
'drunk on music?' is the first definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I can't see?
'impenetrable' is the second definition.
(I've seen this before)
'it's' is the link.
Can you help me to learn more?
(Other definitions for airtight that I've seen before include "securely sealed" , "Totally sealed" , "Hermetically sealed" , "Not allowing gas to pass" , "not letting out a breath?" .)