The most common and most likely answer to this crossword clue is the 9 letter word NEWSAGENT
I've seen this crossword clue in The Daily Telegraph
N
E
W
S
A
G
E
N
T
More clues leading to the result NEWSAGENT
- He supplies daily intelligence on the Scottish factor
- Original wise fellow with Scripture who purveys information
- Replacement spy kidnaps small merchant
- Shop pond life smuggling dope from South Africa?
- Modern US portraitist fires Republican paper supplier
- Retailer offering fresh herb with nuts, oddly
- Philosopher perhaps between novel and religious text in shop
- Retailer fresh on the scene, wise fellow with set of books
- Shopkeeper wants gene mutation
- Shop original man from South Africa?
Buddy explains!

The straight part
We know that "One active in the organ trade" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one active in the organ trade = newsagent.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 NEWSAGENT mean?
NEWSAGENT noun- A retail business selling newspapers, magazines, and stationery; a stationer.
- The proprietor of such a business.