In a colourable manner; in a way that appears plausible or has a seemingly valid appearance.
From 'colourable' + '-ly' (adverbial suffix). This formal adverb modifies verbs and adjectives to describe how something is done in a superficially legitimate manner.
Medieval lawyers loved the adverb 'colourably'—they'd say something was done 'colourably' to mean it seemed legal on the surface even if the true intent was questionable, making it a word that captured the gap between appearances and reality.
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