Hoomans are a race of alien, or species of fantastic creature, or some otherworldly being that are identical in every way to humans, but definitely are not humans. They are often used as a solution to the problem with humans – how do worldbuilders incorporate ‘humans’ into a setting that is not our world and where it would be unlikely to find actual humans? Well, why not use a species that are not humans, but are virtually identical? Those are not humans populating that alien planet millions of years ago, that would be crazy. Those are hoomans.