The most common and most likely answer to this crossword clue is the 9 letter word STRANGLED
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More clues leading to the result STRANGLED
Buddy explains!

The straight part
We know that "stifled" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case stifled = strangled.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 STRANGLED mean?
STRANGLED verb- To kill someone by squeezing the throat so as to cut off the oxygen supply; to choke, suffocate or throttle.
- To stifle or suppress.
- To be killed by strangulation, or become strangled.
- To be stifled, choked, or suffocated in any manner.