unwritten

Adjective

• said or done without having been planned or written in advance
  • he made a few ad-lib remarks
    

• using speech rather than writing
  • an oral tradition
    
  • an oral agreement
    

• 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
    

Related words

• Synonyms: 
  ad-lib , spontaneous , oral