The most common and most likely answer to this crossword clue is the 9 letter word DIAGNOSES
I've seen this crossword clue in The Daily Telegraph
D
I
A
G
N
O
S
E
S
Buddy explains!
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 DIAGNOSES mean?
DIAGNOSES noun- The identification of the nature and cause of an illness.
- The identification of the nature and cause of something (of any nature).
- A written description of a species or other taxon serving to distinguish that species from all others. Especially, a description written in Latin and published.
- To determine which disease is causing a sick person's signs and symptoms; to find the diagnosis.
- (by extension) To determine the cause of a problem.