The most common and most likely answer to this crossword clue is the 10 letter word DECOMPOSED
I've seen this crossword clue in Independent
D
E
C
O
M
P
O
S
E
D
Buddy explains!

The straight part
We know that "broken down" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case broken down = decomposed.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 DECOMPOSED mean?
DECOMPOSED verb- To separate or break down something into its components; to disintegrate or fragment
- To rot, decay or putrefy