The most common and most likely answer to this crossword clue is the 9 letter word TOREADORS
I've seen this crossword clue in The Daily Telegraph
T
O
R
E
A
D
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R
S
More clues leading to the result TOREADORS
Buddy explains!

The straight part
We know that "Fighters" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fighters = toreadors.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 TOREADORS mean?
TOREADORS noun- A bullfighter, especially one on horseback.