Interpolated questionable stretch of inactivity (6,6)

I believe the answer is:

latent period

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'stretch of inactivity' is the definition.
The answer and definition can be both related to time as well as being singular nouns.
Perhaps there's an association between them I don't understand?

'interpolated questionable' is the wordplay.
'questionable' is an anagram indicator.
'interpolated' anagrammed gives 'LATENT PERIOD'.

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I've seen this clue in The Everyman puzzle in The Observer.

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