The most common and most likely answer to this crossword clue is the 9 letter word BREACHING
I've seen this crossword clue in The Daily Telegraph
B
R
E
A
C
H
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N
G
More clues leading to the result BREACHING
Buddy explains!

The straight part
We know that "Breaking" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case breaking = breaching.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 BREACHING mean?
BREACHING verb- To make a breach in.
- To violate or break.
- (of the sea) To break into a ship or into a coastal defence.
- (of a whale) To leap out of the water.
- The act by which something is breached.