unwritten

adjective

1. not actually formulated or expressed; customary; traditional.
2. not written; not put in writing or print; oral: an unwritten agreement.
3. containing no writing; blank.

adjective

1. not printed or in writing
2. effective only through custom; traditional
3. without writing upon it

adj.mid-14c., from un- (1) “not” + past participle of write (v.). Cf. Old English unwriten, Old Norse uritinn.