The most common and most likely answer to this crossword clue is the 10 letter word THREATENED
I've seen this crossword clue in The Daily Telegraph
T
H
R
E
A
T
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N
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D
More clues leading to the result THREATENED
- Trio snatching at Scots hooligan were menacing
- Under attack, extremely tough Red Guards scoffed
- Criminal netted hare potentially facing extinction
- Number, by end of episode in yarn, endangered
- Yarn about Lawrence having opponents browbeaten
- Neater flowing in the delta was imminent
- Intimidated small number clutching at study being overturned
- Pressurised, making a dent there!
- Warned unruly teen to stay in line
- Forecast ill wind to maintain temperature: 67.5 degrees
Buddy explains!

The straight part
We know that "was imminent" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case was imminent = threatened.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 THREATENED mean?
THREATENED verb- To make a threat against someone; to use threats.
- To menace, or be dangerous.
- To portend, or give a warning of.
- To be close to equaling or surpassing (a record, etc.)
- (of a plant or animal) At risk of becoming endangered in the near future.
- Feeling insecure or vulnerable.