means To change something—an institution, law, system, or person—for the better by correcting its flaws and abuses.

from Straight from Latin reformare, 'to form again,' stitching re- ('again') onto formare ('to shape'). It arrived in English through Old French in the late Middle Ages, first carrying a religious weight—amending morals, mending a corrupt life—before it broadened to politics and institutions, where it still promises to remake the broken shape into a better one.