Simply means in a straightforward, uncomplicated way. When your teacher asks you to explain something simply, she wants you to make it clear and easy to understand, without extra complexity or confusing details. If you can explain how photosynthesis works simply, you've found the clearest way to describe it.

The word also means “merely” or “just.” When you say “I simply forgot my homework,” you're emphasizing that there's no complicated excuse or story. It was just forgetfulness, nothing more. Or you might say “She's simply the best singer in the choir” to emphasize a straightforward fact.

In another sense, simply describes living without luxury or excess. Someone who lives simply might have basic furniture, few possessions, and uncomplicated routines. This isn't necessarily about being poor. Some people choose to live simply because they find too many possessions distracting or stressful.

The word carries a positive feeling in most contexts. Simple explanations help people learn. Simple solutions often work better than complicated ones. When something is done simply, it usually means it's been done well, with nothing unnecessary getting in the way of what really matters.