The quality or state of being damning; the degree to which something condemns or incriminates.
From damning (adjective form) plus the noun-forming suffix -ness, which creates abstract nouns. A relatively rare formation from the much more common damning.
This word is so obscure that most English speakers have never encountered it — it's a theoretical noun describing how much something proves guilt, yet almost nobody says it instead of just 'how damning it is.'
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