Unexpected means not anticipated or foreseen: something that catches you by surprise because you had no reason to think it would happen. When your teacher announces an unexpected pop quiz, you hadn't prepared because you thought today would be a regular lesson. When an unexpected package arrives at your door, you weren't waiting for any delivery.

The word captures that moment of surprise when reality doesn't match what you assumed would happen. Sometimes unexpected things are wonderful, like an unexpected snow day or discovering an unexpected talent for playing the saxophone. Other times they're challenging, like an unexpected flat tire on the way to a friend's birthday party or an unexpected ingredient in your lunch that you don't like.

Notice that unexpected is different from rare. A meteor striking your neighborhood would be both unexpected and rare. But your little brother interrupting your homework might be unexpected in the moment, even though it happens a lot: you just weren't thinking about it right then.

People often admire the ability to handle unexpected situations with flexibility and good humor, whether you're solving an unexpected problem in a science experiment or adapting when your soccer game gets moved to an unexpected time.