Someone who knows it's all going to shit, but thinks it will all turn out OK.
There is war, famine, economic collapse, homes being foreclosed, but all this strife makes us stronger and it will all work out in the end, but I'm an apocaloptimist
Someone who knows it's all going to shit, but still thinks things will turn out okay.
Sarah: I'm telling you, in the end he's gonna cheat on you with your sister and your gonna feel betrayed and heartbroken.
Amy: I know, I think so too, but I'm sure it won't be all bad and maybe it won't turn out as bad as you think.
Sarah: Well, way to be an Apocaloptimist.
Someone who knows it's all going to shit, but still thinks it will turn out OK
"It" most commonly refers to the environment, or humanity, but could be other things as well.
Guy 1: "The envrionment is being degraded at an unparalled rate, we're literally destroying ourselves... but, it'll probably turn out OK. If we fail, the planet will likely heal itself in our abscence."
Guy 2: "Man, he's such an apocaloptimist."