The most common and most likely answer to this crossword clue is the 6 letter word ENCAGE
E
N
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A
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E
More clues leading to the result ENCAGE
- Lock up enclosure ahead of time
- Cover of Elton composer put in bars
- Get out the cane, for example, or put into confinement
- Spots rebellious young rogue, finally put behind bars
- Quarantine perhaps, for instance with spots returning
- Close up space next to avant-garde composer
- Say acne is revolting? Shut up!
Buddy explains!

The straight part
We know that "Shut up" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case shut up = encage.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 ENCAGE mean?
ENCAGE verb- To lock inside a cage; to imprison.