The most common and most likely answer to this crossword clue is the 6 letter word BRAKES
I've seen this crossword clue in The Daily Telegraph
B
R
A
K
E
S
More clues leading to the result BRAKES
Buddy explains!

The straight part
We know that "Stops" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case stops = brakes.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 BRAKES mean?
BRAKES noun- A fern; bracken.
- A thicket, or an area overgrown with briers etc.
- A tool used for breaking flax or hemp.
- A type of machine for bending sheet metal. (See wikipedia.)
- A large, heavy harrow for breaking clods after ploughing; a drag.
- To bruise and crush; to knead
- To pulverise with a harrow
- An ancient engine of war analogous to the crossbow and ballista.
- The handle of a pump.
- A device used to slow or stop the motion of a wheel, or of a vehicle, by friction; also, the controls or apparatus used to engage such a mechanism such as the pedal in a car.
- A baker's kneading trough.
- A device used to confine or prevent the motion of an animal.
- That part of a carriage, as of a movable battery, or engine, which enables it to turn.
- To operate (a) brake(s).
- To be stopped or slowed (as if) by braking.
- A cage.
- A type of torture instrument.