Unwritten (4)
'unwritten' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for oral that I've seen before include "Spoken test" , "By word of mouth, like some exams" , "By word of mouth, say exam" , "Kind of exam" , "Relating to the mouth - exam" .)
(Other definitions for erased that I've seen before include "Rubbed out, expunged" , "torn off" , "deleted material" , "Rubbed out, deleted" , "'Wiped out, deleted (6)'" .)