Uninsured describes someone (or something, like a car or a house) that does not have insurance - meaning if something goes wrong, like an accident, a fire, or a sickness, there's no insurance company to help pay for it. This word is very common in the news, especially in countries like the U.S. where health insurance isn't free or automatic - 'the uninsured' often refers to people who don't have health insurance and have to pay their own medical bills.