California Gov. Jerry Brown (D) compared Trump supporters to Neanderthal-era cave-dwellers at a global warming speech in New York City.
He said the "derivation" of the term "Trump-ite" is similar to that of "troglodyte," which is the scientific term for cavemen.
"You should check out the derivation of Trump-ite and troglodyte, because they both refer to people who dwell in deep dark caves," he said, according to Politico.
Brown made the comparison due to the fact that some Trump supporters are skeptical of climate change forces and that the president himself has distanced the United States from the Paris Climate Accord.
"President Trump is the null hypothesis. Everything he's doing is stupid, dangerous and silly," Brown said.
Brown ripped Trump for referring to North Korean dictator Kim Jong-Un as "rocket man," calling the New Yorker "absurd."
He remarked that it is only a matter of time before other "economic and international forces" gain prominence and tell Trump "you're fired."