Nobody knows where the word “jazz” originated. It feels today like something that’s always been. A vivid monosyllable—like dawn, or ash. Like the color blue. It might come from the French word jaser, chitchat, or from their word for hunting, chasser. It might have been invented by Titanic-era baseball players, who called their wobbliest pitches “jazz balls.” Many scholars tie “jazz” to “jasm,” an archaic term for energy, spirit or semen.

Somehow all of these explanations feel true. Jazz is dirty and spiritual; it’s playful talk and murderous pursuit; it’s a dancing object as it moves through the air.

It can also be painfully dull. While “jazz” is hot-blooded and beautiful, “jazzy” is almost always flaccid and false. At its worst, or to the heedless listen...