The most common and most likely answer to this crossword clue is the 8 letter word REPRISAL
I've seen this crossword clue in Financial Times
R
E
P
R
I
S
A
L
More clues leading to the result REPRISAL
- Way of getting back voting system one’s not imagined being without
- Prince is detained in genuine act of vengeance
- Theatre hands round account showing revenge
- Aspire to move between sides as retaliation
- Rare slip somehow results in act of retaliation
- Salesperson returning city gentleman’s payback
- Rips off in authentic vengeful act
- Jail’s not on – it impedes genuine vengeance
- Priest is stopping money as act of vengeance
- Prince is detained in serious act of vengeance
Buddy explains!

The straight part
We know that "vengeance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vengeance = reprisal.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 REPRISAL mean?
REPRISAL noun- An act of retaliation.
- Something taken from an enemy in retaliation.
- The act of taking something from an enemy by way of retaliation or indemnity.