Hoary means gray or white with age, like an old man's beard that's turned silvery, or frost covering a winter field at dawn. When something is hoary, it looks ancient and weathered by time.

You'll often see this word describing things that have literally turned gray: hoary tree branches covered in ice crystals, or the hoary fur of an old dog whose muzzle has whitened over the years. The hoary marmot, a large ground squirrel found in mountain regions, gets its name from the silvery-gray fur on its shoulders and head.

The word also describes ideas, jokes, or stories that are so old they've grown stale. A hoary joke is one your grandfather might have told, one that's been repeated so many times it's lost its freshness. When someone dismisses a hoary old myth or a hoary tradition, they mean it's ancient and perhaps outdated.