The most common and most likely answer to this crossword clue is the 6 letter word CEASES
I've seen this crossword clue in The Guardian
C
E
A
S
E
S
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 = ceases.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 CEASES mean?
CEASES verb- To stop.
- To stop doing (something).
- To be wanting; to fail; to pass away.