In a manner that functions as an adjective modifying a noun; in an adnominal way.
From 'adnominal' plus the adverb-forming suffix '-ly.' This adverb form allows speakers to describe how a word is being used grammatically.
This is one of those rare words that linguists love—it's basically saying 'in the way that an adjective attaches to a noun,' which is so meta-linguistic it makes grammar nerds smile.
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