illegible• I don't know what this note says - Dad's handwriting is totally illegible!• Ron's handwriting is completely illegible.• The label had got wet and was now illegible.• The check was signed by an officer of the bank whose first name was Thomas; the last name was illegible.• The other five pages, Julia saw, were all illegible.• Extended writing projects are usually beyond their capabilities, and what is produced may be illegible and of poorquality.• Most of it was either illegible or written in Latin.• Some pages were long, illegible, others no more than a line.• When it comes to healthcare, illegiblescript can be dangerous, if not deadly.• Pictures were almost non-existent, long columns of grey, illegible type propped up its pages.
From Longman Business Dictionary
illegibleil·le·gi·ble /ɪˈledʒəbəl/adjectiveadj
not written or printed clearly, and difficult or impossible to read
Midwest refused to honor the check, saying that the endorsement was illegible.