The most common and most likely answer to this crossword clue is the 7 letter word STUNNER
I've seen this crossword clue in The Daily Telegraph
S
T
U
N
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More clues leading to the result STUNNER
Buddy explains!
The straight part
We know that "sensation" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sensation = stunner.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 STUNNER mean?
STUNNER noun- Anything that is stunning.
- A professional wrestling maneuver in which an attacking wrestler applies a facelock to an opponent and falls to a seated position, forcing the opponent's jaw or neck to drop on the attacker's shoulder.
- A pistol firing a beam capable of stunning an enemy.
- A person or machine that stuns an animal before slaughter.