Heavens, Excellency! (8)

I believe the answer is:

goodness

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'heavens excellency' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.

This is the entire clue.

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(Other definitions for goodness that I've seen before include "Virtue; excellence" , "merit" , "Quality of being morally good or virtuous" , "Virtue, rightness" , "Exclamation of surprise" .)

I've seen this clue in the Evening Standard.

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