The most common and most likely answer to this crossword clue is the 9 letter word LEUKAEMIA
I've seen this crossword clue in The Guardian
L
E
U
K
A
E
M
I
A
Buddy explains!
The straight part
We know that "blood disorder" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case blood disorder = leukaemia.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 LEUKAEMIA mean?
LEUKAEMIA noun- A type of malignancy affecting the blood cells or blood-forming tissues.
- Any specific form or type of cancer of the blood-forming tissues.