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 資料よりも慣習に基づいた。
日/英 »
using speech rather than writing; "an oral tradition"; "an oral agreement" 日/英 »
said or done without having been planned or written in advance; "he made a few ad-lib remarks" 日/英 »
