In a biased manner; with prejudice or unfair preference for one side.
From 'bias' (probably from Occitan 'biais' meaning slant) with the adverbial suffix '-ly.' The formation parallels 'biased' + '-ly.'
Although grammatically correct, 'biasedly' is almost never used—people prefer 'with bias' or 'biasedly'—showing how some theoretically possible words just don't survive in actual language.
Complete word intelligence in one call. Free tier — 50 lookups/day.