Tossing and turning, unlike princess awakened by a kiss? (9)

I believe the answer is:

sleepless

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'tossing' is the definition.
Both the definition and answer are adjectives. Perhaps there's a link between them I don't understand?

I cannot understand how the rest of the clue works.

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(Other definitions for sleepless that I've seen before include "Insomniac" , "Suffering from insomnia, not in the land of Nod" , "Film: '-- in Seattle'" .)

I've seen this clue in The Times.

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