Fast asleep, universally shunned (4,2,3,5)

I believe the answer is:

dead to the world

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'fast asleep' is the definition.
(dead to the world can mean asleep)

I don't understand how the rest of the clue works.

(Other definitions for dead to the world that I've seen before include "Fast asleep" , "Sound asleep; unconscious" , "Sleeping" .)

I've seen this clue in The Daily Express.

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