The most common and most likely answer to this crossword clue is the 9 letter word LIGHTNING
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More clues leading to the result LIGHTNING
- Striker having a harmful effect, ignoring leader about Nationalist
- Inside of jacket keeps hot amid great burst of energy
- A bolt from the blue
- Weather conditions providing illumination around the beginning of night
- Evidence of storm easing when energy is lost
- Thunderous accompaniment from inn rocking during torch song’s climax
- Settling about name very fast
- Becoming more cheerful without Ecstasy – that’s impetuous!
- Sudden lack of energy during weight loss
- Fireball illuminating northern parts
Buddy explains!

The straight part
We know that "Thunderous accompaniment" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case thunderous accompaniment = lightning.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 LIGHTNING mean?
LIGHTNING noun- A flash of light produced by short-duration, high-voltage discharge of electricity within a cloud, between clouds, or between a cloud and the earth.
- A discharge of this kind.
- Anything that moves very fast.
- The act of making bright, or the state of being made bright; enlightenment; brightening, as of the mental powers.
- To produce lightning.
- Extremely fast or sudden; moving (as if) at the speed of lightning.