The most common and most likely answer to this crossword clue is the 9 letter word CASCADING
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More clues leading to the result CASCADING
Buddy explains!

The straight part
We know that "Falling" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case falling = cascading.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 CASCADING mean?
CASCADING verb- To fall as a waterfall or series of small waterfalls.
- To arrange in a stepped series like a waterfall.
- To occur as a causal sequence.
- To vomit.