The most common and most likely answer to this crossword clue is the 9 letter word TERRORISM
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More clues leading to the result TERRORISM
- “Blunder in obscure mist,” as a dictator characterizes protests against his regime?
- Note broken mirrors creating a source of danger
- Fundamentalist error is made embracing political violence
- Mistake in swirling mist may bring state of fear
- Extremist action essentially protects broken mirrors
- Flaw is found in disheartened team's intimidatory tactics
Buddy explains!

The straight part
We know that "Extremist action/" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case extremist action/ = terrorism.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 TERRORISM mean?
TERRORISM noun- The deliberate commission of an act of violence to create public fear through the suffering of the victims in the furtherance of a political or social agenda.
- The use of unlawful violence against people or property to achieve political objectives.
- A form of psychological manipulation through warfare to the purpose of political or religious gains, by means of deliberately creating a climate of fear amongst the inhabitants of a specific geographical region.