Unreasonably means in a way that goes beyond what makes sense or what's fair. When someone acts unreasonably, they're being excessive, illogical, or refusing to listen to good sense.

If your friend gets unreasonably angry because you picked pepperoni pizza instead of cheese, their reaction is way too extreme for such a small thing. If a teacher gives an unreasonably difficult test that covers material never taught in class, the test doesn't match what's fair or logical. When a store charges unreasonably high prices, like fifty dollars for a pencil, the cost is absurd compared to the item's actual value.

The word often appears when someone won't budge from a position even when presented with facts or logic. A person being unreasonably stubborn might refuse to wear a coat in a snowstorm, ignoring both common sense and everyone's advice.

Notice that unreasonably is different from simply being wrong. Someone can make an honest mistake and still be reasonable. But when someone is unreasonably demanding, unreasonably suspicious, or unreasonably critical, they've crossed a line into behavior that others recognize as excessive or unfair. The word captures that moment when something stops being justified and starts being over the top.