Doubly means twice as much, or in two different ways at once. When something is doubly difficult, it's difficult for two separate reasons. If you're doubly sure about an answer, you've checked it two different ways to be certain.

The word often emphasizes how two factors combine to make something stronger or more intense. A student who forgot to study and also slept through their alarm might feel doubly worried about arriving late to an important test. A gift that's both thoughtful and beautifully wrapped is doubly appreciated.

You might say someone is doubly lucky if they won a raffle and also got a snow day on the same day, meaning their good fortune came from two separate sources. When a teacher says “You need to be doubly careful in this experiment,” they're telling you to pay extra attention because the stakes are higher than usual. The word helps us describe when two things pile up together, whether that makes a situation twice as good or twice as challenging.