54 synonyms for outdated such as antediluvian, anachronistic, and ancient. Outdated is an adjective, and its antonyms are current, modern, and fashionable.
Anachronistic, ancient, antediluvian, antiquated, antwacky, archaic, backward-looking, behind the times, behindhand, bygone, clunky, creaky, crusted, démodé, dated, defunct, feudal, former, fusty, horse-and-buggy, medieval, mossy, moth-eaten, mouldy, musty, not with it, obsolescent, obsolete, old, old hat, old-fangled, old-fashioned, old-fogeyish, old-time, old-world, olde worlde, out, out of date, out of fashion, out of style, out of the ark, outmoded, outworn, passé, past, prehistoric, quaint, rinky-dink, square, square-toed, superannuated, unfashionable, and vieux jeu.