means A person or machine that harvests ripe grain or other crops, or — by grim metaphor — a personification of death who cuts down the living like wheat.

from From Old English 'rīpan,' to reap or cut grain, which gave us the agent noun 'reaper,' literally one who reaps. For centuries it meant exactly that: a farmhand swinging a scythe through autumn fields. The leap to Death came later, when poets and painters fixed on the bleak harvest image — souls as crops, the scythe as the great equalizer — and crowned the figure the Grim Reaper, where 'grim' carries its old weight of 'fierce, cruel.'