The most common and most likely answer to this crossword clue is the 11 letter word INTIMIDATES
I've seen this crossword clue in The Times
I
N
T
I
M
I
D
A
T
E
S
Buddy explains!

The straight part
We know that "bullies" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bullies = intimidates.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.
Crossword Answer definitions
INTIMIDATES verb- To make timid or afraid; to cause to feel fear or nervousness; to deter, especially by threats of violence