(s)antediluvian, antiquated, archaicso extremely old as seeming to belong to an earlier period“a ramshackle antediluvian tenement”, “antediluvian ideas”, “archaic laws”
(s)archaic, primitivelittle evolved from or characteristic of an earlier ancestral type“archaic forms of life”, “primitive mammals”, “the okapi is a short-necked primitive cousin of the giraffe”