Active describes someone or something that's moving, working, or involved rather than sitting still or doing nothing. An active student participates in class discussions, raises their hand with questions, and engages with the material instead of passively listening. An active volcano can still erupt, unlike an extinct one that's finished for good.

The word suggests energy and engagement. When you're active in a club or sport, you don't just show up: you contribute, help make decisions, and take part in activities. Your body needs active time each day, meaning periods when you're running, playing, or moving rather than sitting on the couch.

In grammar, the active voice means the subject does the action: “The dog chased the ball.” This differs from the passive voice, where the action happens to the subject: “The ball was chased by the dog.” Active voice usually makes writing clearer and more direct.

Scientists use active to describe things currently working or reacting. An active ingredient in medicine is the part that actually treats your symptoms. An active email account is one you still use, not an old abandoned one.

The opposite of active is passive (not participating) or inactive (not moving or working). When you're active, you're making things happen rather than waiting for things to happen to you.