The most common and most likely answer to this crossword clue is the 8 letter word SHATTERS
I've seen this crossword clue in The Guardian
S
H
A
T
T
E
R
S
Buddy explains!

The straight part
We know that "breaks" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case breaks = shatters.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 SHATTERS mean?
SHATTERS verb- To violently break something into pieces.
- To destroy or disable something.
- To smash, or break into tiny pieces.
- To dispirit or emotionally defeat
- To scatter about.