The most common and most likely answer to this crossword clue is the 3 plus 6 letter word ILL HEALTH
I
L
L
H
E
A
L
T
H
More clues leading to the result ILL HEALTH
- One tiny bit of laudanum will finally cure the unending sickness
- Infirmity deteriorating till cure inside hospital
- Grotty toast leads to sickness
- Sickness from crummy toast
- One is well rid of it
- I will cure half of this sickness
- Poor condition of Leith Hall after renovation
- Personal problem or line adopted by PM once on the inside of mills
- Sick condition of all the legendary, iconic leaders treated at hospital
Buddy explains!

The straight part
We know that "Sick" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sick = ill health.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.