The most common and most likely answer to this crossword clue is the 9 letter word BONAPARTE
I've seen this crossword clue in The Sunday Telegraph
B
O
N
A
P
A
R
T
E
More clues leading to the result BONAPARTE
- Corsican holding up a toff, left without diamonds
- In dire trap, a nobleman’s backing emperor
- A Bronte composition about father’s house in Corsica
- During battle, trap a noble mounted general
- Emperor a bit overwhelmed by the hard stuff
- General finds equal among British — near Darjeeling mostly?
- Malleus, say, assumed a role of an emperor
- Old leader getting on a bit, virtually bedbound?
- Dictator having a role in something contentious?
- French emperor is aloof, wearing off-white
Buddy explains!
The straight part
We know that "Emperor" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case emperor = bonaparte.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.