Obsessive way - zero sound (12)
I believe the answer is:
pathological
'obsessive' is the definition.
Both the answer and definition are adjectives. Perhaps there's an association between them I don't understand?
'way zero sound' is the wordplay.
I cannot quite understand how this works, but
'way' could be 'path' (path is a kind of way) and 'path' is located in the answer.
'zero' could be 'o' (O resembles 0) and 'o' is found within the answer.
'sound' could be 'logical' (I've seen this in another clue) and 'logical' 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 pathological that I've seen before include "Relating to or exhibiting disease" , "Unhealthy - compulsive" .)