A connoisseur is someone who knows a great deal about a kind of art, food, drink, or music, and who can tell a fine thing from an ordinary one. It is not only book knowledge: they have trained their eye, ear, or tongue, and they care about small differences other people miss. You hear it most with wine, coffee, cheese, painting, and classical music. The word feels a little high and fancy. Friends often say it with a smile — “listen to the tea connoisseur” — as if the person were showing off. You rarely call yourself one unless you are joking; other people give you that name. Though actually, shops and magazines now stretch it a long way, for almost anyone who likes a thing a lot, expert or not. In careful use, liking is not enough. A fan is loud and eager; a connoisseur is picky and informed.