unwritten
     adj 1: based on custom rather than documentation; "an unwritten
            law"; "rites...so ancient that they well might have
            had their unwritten origins in Aurignacian times"-
            J.L.T.C.Spence [ant: {written}]
     2: using speech rather than writing; "an oral tradition"; "an
        oral agreement" [syn: {oral}]
     3: said or done without having been planned or written in
        advance; "he made a few ad-lib remarks" [syn: {ad-lib}, {spontaneous}]
Source: WordNet® 2.0