in a manner relating to or suitable for courts of law or legal proceedings.
From 'forensical' with the adverbial suffix '-ly' (from Old English), turning an adjective into an adverb describing how something is done.
This is the modern form you'd actually hear today—'forensically examined' or 'forensically sound'—showing how the 'fore-' prefix words were largely replaced by simpler Latin-rooted terms.
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