Neanderthal refers to an extinct species of humans who lived in Europe and Asia from about 400,000 to 40,000 years ago. The name comes from the Neander Valley in Germany, where scientists first discovered their fossils in 1856.

Neanderthals were remarkably similar to modern humans but had some distinct features: stockier builds, prominent brow ridges, and larger noses that may have helped them survive Ice Age cold. They were skilled toolmakers, hunted large animals, cared for their sick and injured, and even buried their dead with what appears to be ceremony. Recent DNA evidence shows that modern humans and Neanderthals interbred when they encountered each other, which means many people today carry small amounts of Neanderthal DNA.

The word is also used informally (and somewhat unfairly to actual Neanderthals) as an insult meaning someone crude, brutish, or intellectually backward. If someone calls another person a Neanderthal, they're suggesting that person lacks sophistication or modern thinking. This usage stems from outdated ideas about Neanderthals being primitive cave people, when in reality they were intelligent, resourceful humans who thrived for hundreds of thousands of years in challenging environments.