tree hugger vs environmentalist

tree hugger and environmentalist both are nouns.

Word	Noun	Adjective	Verb	Adverb
tree hugger	Yes	No	No	No
environmentalist	Yes	No	No	No

As nouns, environmentalist is a hypernym of tree hugger; that is, environmentalist is a word with a broader meaning than tree hugger:

tree hugger: derogatory term for environmentalists who support restrictions on the logging industry and the preservation of forests
environmentalist: someone who works to protect the environment from destruction or pollution

Other hypernyms of tree hugger include conservationist.

tree hugger (noun)	environmentalist (noun)
derogatory term for environmentalists who support restrictions on the logging industry and the preservation of forests	someone who works to protect the environment from destruction or pollution