The most common and most likely answer to this crossword clue is the 6 letter word ALARUM
I've seen this crossword clue in Independent
A
L
A
R
U
M
More clues leading to the result ALARUM
Buddy explains!

The straight part
We know that "commotion" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case commotion = alarum.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 ALARUM mean?
ALARUM noun- A danger signal or warning.
- A call to arms.
- To sound alarums, to sound an alarm.