The most common and most likely answer to this crossword clue is the 13 letter word DISINTEGRATED
I've seen this crossword clue in The Daily Telegraph
D
I
S
I
N
T
E
G
R
A
T
E
D
Buddy explains!
The straight part
We know that "broken into smaller units" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case broken into smaller units = disintegrated.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 DISINTEGRATED mean?
DISINTEGRATED verb- To undo the integrity of, break into parts.
- To fall apart, break up into parts.
- That has undergone disintegration