The most common and most likely answer to this crossword clue is the 8 letter word DEAFNESS
I've seen this crossword clue in The Times
D
E
A
F
N
E
S
S
Buddy explains!
The straight part
We know that "Inability to hear/case" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case inability to hear/case = deafness.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DEAFNESS mean?
DEAFNESS noun- The condition of being deaf; the lack or loss of the ability to hear.
- Lack of knowledge or refusal to admit a particular problem, issue, etc.