The most common and most likely answer to this crossword clue is the 8 letter word BLOWBACK
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More clues leading to the result BLOWBACK
Buddy explains!
The straight part
We know that "unwanted repercussion" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unwanted repercussion = blowback.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 BLOWBACK mean?
BLOWBACK noun- A type of action where the pressure from the fired cartridge blows a sliding mechanism backward to extract the fired cartridge, chamber another cartridge, and cock the hammer.
- An unintended adverse result, especially of a political action.
- The act of shotgunning (inhaling from a pipe etc. and exhaling into another smoker's mouth).
- On a steam locomotive, the reversal of exhaust gases when the regulator is closed without using the blower; see Blowback (steam engine).