An environmentalist is someone who works to protect nature and keep our planet healthy. Environmentalists care deeply about issues like clean air and water, preserving forests and wildlife, and preventing pollution. Some environmentalists work as scientists studying climate or endangered species, while others might organize community cleanup days or advocate for laws that protect natural resources.

The word comes from environment, which means the natural world around us: the air we breathe, the water we drink, the soil that grows our food, and the ecosystems where plants and animals live. An environmentalist believes these things need active protection because human activities can damage them.

You might encounter environmentalists in many contexts. A marine biologist studying coral reefs is an environmentalist. So is someone who starts a recycling program at their school, a park ranger protecting wilderness areas, or a politician writing legislation to reduce air pollution.

Being an environmentalist doesn't require a specific job or political view. It can mean caring about the natural world and taking action to protect it. When people pick up litter at the park or help their family conserve water during a drought, they are acting like environmentalists. The word describes both professional conservationists and ordinary people who want to leave the planet in good condition for future generations.