Has such an egg been stolen? (7)

I believe the answer is:

poached

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'stolen?' is the definition.
Both the definition and answer are adjectives. Maybe you can see an association between them that I don't see?

I can't explain the rest of the clue.

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(Other definitions for poached that I've seen before include "taken illegally" , "Like many an egg" , "Cooked eggs" , "Stolen - cooked in hot water" , "Illegally hunted (game)" .)

I've seen this clue in the Evening Standard.

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