The most common and most likely answer to this crossword clue is the 9 letter word INTESTINE
I've seen this crossword clue in Financial Times
I
N
T
E
S
T
I
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E
More clues leading to the result INTESTINE
- One figure touring river or part of canal?
- More than just the colon during exam in English?
- . Queen barred from engaging, mostly, with bit of effervescence in bowel
- Gut instinct’s three-quarters about outwardly tangible energy
- Under evaluation at home, electronic digestion mechanism
- During trial I navigate vacated section of canal
- In pain? Test in elongated part of gut
- Organ is faintest in echoing section
- Passage from current examination in English
- In pain, test in every part of the body
Buddy explains!

The straight part
We know that "Organ" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case organ = intestine.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 INTESTINE mean?
INTESTINE noun- (often pluralized) The alimentary canal of an animal through which food passes after having passed all stomachs.
- One of certain subdivisions of this part of the alimentary canal, such as the small or large intestine in human beings.
- Domestic; taking place within a given country or region.
- Internal.
- Depending upon the internal constitution of a body or entity; subjective.
- Shut up; enclosed.