"The name of the machine in which the axe descends in grooves from a considerable height so that the stroke is certain and the head instantly severed from the body." [Universal Magazine of Knowledge and Pleasure, January 1793], 1791, from French guillotine, named in recognition of French physician Joseph Guillotin (1738-1814), who as a deputy to the National Assembly (1789) proposed, for humanitarian and efficiency reasons, that capital punishment be carried out by beheading quickly and cleanly on a machine, which was built in 1791 and first used the next year. Similar devices on similar principles had been used in the Middle Ages. The verb is attested by 1794. Related: Guillotined; guillotining.
This is the product of Guillotin's endeavors, ... which product popular gratitude or levity christens by a feminine derivative name, as if it were his daughter: La Guillotine! ... Unfortunate Doctor! For two-and-twenty years he, unguillotined, shall hear nothing but guillotine, see nothing but guillotine; then dying, shall through long centuries wander, as it were, a disconsolate ghost, on the wrong side of Styx and Lethe; his name like to outlive Cæsar's. [Carlyle, "French Revolution"]