Definition & Meaning of "greeniac"in English

What is the origin of the term "greeniac" and how is it used?

"greeniac" is a slang term that emerged in the late 20th century, combining "green," associated with environmentalism, and "-niac," a suffix denoting obsession or fanaticism, to label someone as an extreme or fanatical environmental activist. The word draws on exaggeration to suggest overzealousness or uncompromising behavior. It appears in informal speech, media commentary, and sometimes political discourse, often used by critics of environmental activism. The term is derogatory or mocking, context-dependent, and intended to belittle perceived extremism; it is not neutral.