Magnificently is how you say something is done, or how it looks, in a magnificent way: very well, very beautifully, very impressively. She sang magnificently. The room was magnificently lit. It is an adverb, so it tells you about a verb or about a whole scene, not the name of a thing. It is a little formal and a little glowing — you use it when you really mean “wow,” not for a sandwich that was merely fine. Though actually, speakers sometimes use it with a smile, almost as praise with extra cream: “You did magnificently.”