In a manner that is out of chronological order or belonging to the wrong time period.
From 'anachronical' + '-ly' (manner, forming adverbs). Creates the adverbial form to describe how something is done anachronistically.
When you add '-ly' to temporal adjectives, you're describing how actions defy time—'anachronically speaking' means your whole argument is temporally wrong, a useful phrase for historians critiquing bad scholarship.
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