Heavens, is that why you were never smacked as a child? (8)

I believe the answer is:

goodness

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'heavens is that why you were never smacked as a child?' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.

This is the entire clue.

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(Other definitions for goodness that I've seen before include "merit" , "Morality, generosity, kindness" , "Virtue, righteousness" , "Moral excellence" , "Virtue; excellence" .)

I've seen this clue in the Evening Standard.

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