adj. 25B6; adjective
prehistoric times : PRIMITIVE, primeval, primordial, primal, ancient, early, antediluvian.
(informal) the special effects look prehistoric : OUT OF DATE, outdated, outmoded, old-fashioned, démodé, passé, antiquated, superannuated, archaic, behind the times, primitive, antediluvian; informal out of the ark; Brit. informal past its sell-by date; N. Amer. informal horse-and-buggy, clunky.
archaeo-.
modern.