In a word, wrongness (8,7)

I believe the answer is:

indirect antonym

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'wrongness' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.

'in a word' is the wordplay.
'a word' becomes 'directantonym' (direct antonym is a kind of word).
'in'+'directantonym'='INDIRECT ANTONYM'

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I've seen this clue in The Daily Express.

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