The most common and most likely answer to this crossword clue is the 7 plus 1 plus 4 letter word CAUSING A STIR
I've seen this crossword clue in The Guardian
C
A
U
S
I
N
G
A
S
T
I
R
Buddy explains!
The straight part
We know that "Provoking activity" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case provoking activity = causing a stir.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.