The most common and most likely answer to this crossword clue is the 12 letter word HYPOCHONDRIA
I've seen this crossword clue in The Daily Telegraph
H
Y
P
O
C
H
O
N
D
R
I
A
More clues leading to the result HYPOCHONDRIA
Buddy explains!
The straight part
We know that "Feeling virtually sick" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case feeling virtually sick = hypochondria.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 HYPOCHONDRIA mean?
HYPOCHONDRIA noun- A psychological disorder characterized by excessive preoccupation or worry about having a serious illness.
- Melancholy; depression
- The upper region of the abdomen, below the lower ribs, each side of the epigastrium.