illegibleil‧le‧gi‧ble /ɪˈledʒəbəl/ adjective 
His handwriting is totally illegible.—illegibly adverb—illegibility /ɪˌledʒəˈbɪləti/ noun [uncountable]
EXAMPLES FROM OTHER DICTIONARIES
- 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.
- Extended writing projects are usually beyond their capabilities, and what is produced may be illegible and of poor quality.
- Most of it was either illegible or written in Latin.
- Pictures were almost non-existent, long columns of grey, illegible type propped up its pages.
- Some pages were long, illegible, others no more than a line.
- 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.
- When it comes to health care, illegible script can be dangerous, if not deadly.
Longman Language Activatordifficult or impossible to read
especially spoken use this to say that you are unable to read someone's writing: · I can't read the next word.· She couldn't read the name on the envelope.
informal use this to say that you are unable to read a particular word because it is not written clearly: · I couldn't make out the name at the bottom of the letter.
writing that is illegible is impossible to read because it is not written clearly: · I don't know what this note says - Dad's handwriting is totally illegible!· The label had got wet and was now illegible.
writing that is indecipherable is impossible to read because it is very untidy, very unclear, or is in a language you do not understand: · The painting had an indecipherable signature in the corner.· His writing was tiny and indecipherable.· I received a blurred, indecipherable fax that didn't help at all.
writing that is unreadable is impossible to read because it is very untidy or unclear: · The photocopy was poorly produced and almost unreadable.
something that someone has written in a very untidy way which is very difficult to read: · I couldn't read the doctor's scrawl.· I kept a diary then -- pages and pages of tiny scrawl.
COLLOCATIONS FROM OTHER ENTRIES Her signature is totally illegible (=cannot be read).
difficult or impossible to read OPP legible: (=written clearly/not written clearly enough for you to read)· He writes very quickly and his handwriting is almost illegible.
Her signature is totally illegible (=cannot be read). His handwriting is totally illegible.—illegibly adverb—illegibility /ɪˌledʒəˈbɪləti/ noun [uncountable]