In a way that shows great skill or knowledge; with expert ability.
From adept (Latin adeptus, 'obtained' or 'skilled') plus -ly (adverb-forming suffix). The root suggests someone who has 'attained' mastery through practice.
The word adept originally meant someone who had achieved mastery in alchemy or secret knowledge, so calling someone adept literally meant they'd unlocked hidden expertise—pretty cool for a skill descriptor!
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