1650s, "walk, step, manner of proceeding," from French démarche (15c.) literally "gait, walk, bearing," from démarcher (12c.) "to march," from de- (see de-) + marcher (see march (v.)). Meaning "a diplomatic step" attested from 1670s. A word never quite nativized, though it appears in Century Dictionary (1897) as demarch.