The most common and most likely answer to this crossword clue is the 8 letter word CARILLON
I've seen this crossword clue in Financial Times
C
A
R
I
L
L
O
N
More clues leading to the result CARILLON
- Festively singin’ with head of orchestra and I swapping bells
- Prisoner holding a little flower set to be hung in Tower
- Vehicle badly functioning? Stop
- Bells ring round parish centre, one nonstop
- Set that may ring or call in poorly
- May goes round Welsh resort, we hear, with nothing on, just a set of bells
- Rook I let in to visit occupant of bell tower
- Fifty joining in in carol with shaking bells
- Runs into weird local in ‘Ring O’Bells‘
- Vehicle with poorly running set of ringers
Buddy explains!

The straight part
We know that "Stop" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case stop = carillon.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 CARILLON mean?
CARILLON noun- A set of bells, often in a bell tower, sometimes operated by means of a keyboard (manual or pedal), originating from the Low Countries.
- A tune adapted to be played by musical bells.