To do something purposely means to do it on purpose, deliberately and intentionally. When you act purposely, you know exactly what you're doing and you mean to do it.

If you purposely arrive early to help your teacher set up the classroom, you planned to get there ahead of time. If you purposely choose the harder math problem to challenge yourself, you made that choice knowingly. The word tells us that something wasn't an accident, mistake, or coincidence.

Purposely is different from accidentally. If you accidentally knock over a glass of water, you didn't mean for it to happen. But if you purposely pour water on a plant, you intended to do exactly that.

People sometimes confuse purposely with purposefully, but they mean different things. When you do something purposefully, you're doing it with determination and a sense of purpose, like walking purposefully toward a goal. When you do something purposely, you're simply doing it on purpose. You might purposely take the long way home (meaning you chose that route intentionally), or you might walk purposefully toward the finish line (meaning you're walking with strong determination).