Moropus is related to the modern horse, rhino, and tapir.
Moropus was named by Marsh (1877). Its type is Moropus distans. It was synonymized subjectively with Macrotherium by Osborn (1893). It was assigned to Moropodidae by Marsh (1877); to Chalicotheriidae by Marsh (1877), Peterson (1907), Skinner (1968), Coombs (1978), Carroll (1988), Coombs (1998) and Holbrook (1999); and to Schizotheriinae by Geraads et al. (2007).
Like other chalicotheres, they differed from their modern relatives in having large claws, rather than hooves, on the front feet; these claws may have been used for defense or digging for food. Moropus stood about 8 feet (2.4 m) tall at the shoulder. The three highly compressed claw-like hooves on each foot were split down the middle. These claws actually gave Moropus its name: " slow "or "sloth foot". This name implies that because of the claws, Moropus was a clumsy mover. But the articulation of the phalangeal (finger) bones, in addition to probable large foot and toe pads, shows that Moropus probably could raise the claws slightly to enable it to move about quite smoothly. Because the hooves curve inward, it probably had a pigeon-toed gait.