Grizzly comes from the English word for the bear, giving it a rugged, wild-nature association.
Grizzly derives from "grizzled," itself from the Old French "grisel" meaning gray or streaked with gray, first applied to the great North American brown bear (Ursus arctos horribilis) whose silver-tipped fur gave it a salt-and-pepper appearance to early naturalists and trappers. The grizzly bear became one of the defining symbols of the American wilderness — featured on the California state flag since 1846, immortalized in the journals of Lewis and Clark, and central to the spiritual cosmology of dozens of Pacific Northwest Indigenous nations, for whom the bear was a figure of tremendous power, healing, and kinship with humanity. In the nineteenth century, grizzly entered American vernacular as an adjective of raw, almost mythic toughness.
Mountain men competed to tell grizzly-encounter stories; James Capen Adams, known as "Grizzly Adams," became a folk hero in the 1850s by capturing and taming grizzlies in the Sierra Nevada. The bear's eventual near-extinction from California by the early twentieth century gave the name an elegiac quality — a symbol of wild America that slipped away. As a human given name, Grizzly occupies the very outer edge of the American nature-name frontier, beyond even the rugged Wilder or Ranger and into fully untamed territory.
It signals parents who value unbridled strength and wilderness identity above all social convention. There are no literary heroes or historical statesmen named Grizzly — only the bear itself, massive and legendary, which may be precisely the point.