Perhaps inspired by the slang term "oreo", anti-environmentalists cooked up the word "watermelon" as a derogatory slang term for environmentalists. The logic is this: environmentalists may be "green" (pro-environment) on the outside, but on the inside they are really "red" (communist). A big hit in the heartland, perhaps, but those of us who realize that the Cold War ended a long time ago just roll our eyes.