A person who is concerned about protecting nature and the environment, and who supports conservation and reduction of pollution.
From 'environment' (from Old French 'environ' meaning 'around') plus 'mental' (of the mind) plus the agent suffix '-ist' (one who does or believes something). The term became common in the 1960s-70s environmental movement.
The word 'environmentalist' only became common in the last 60 years—before that, people concerned with nature were 'conservationists' or 'naturalists.' The name changed because the scope of concern expanded from protecting specific places to protecting Earth's systems.
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