The most common and most likely answer to this crossword clue is the 7 letter word FOMENTS
I've seen this crossword clue in The Daily Telegraph
F
O
M
E
N
T
S
Buddy explains!

The straight part
We know that "Instigates" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case instigates = foments.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 FOMENTS mean?
FOMENTS verb- To incite or cause troublesome acts; to encourage; to instigate.
- To apply a poultice to; to bathe with a cloth or sponge.