Difficult or impossible to read

Illegible (Adjective)
If a writing or a print is illegible, it is so unclear and untidy or too small that you cannot read it .

- Damaged,defaced or illegible entries will be disqualified.
- His writing is almost illegible.

Unreadable (Adjective)
A writing which is impossible to read because of being messy, untidy,unclear or especially damaged.

- The labels were blurred and unreadable.
- The documents were unreadable because of microscopic print.


Indecipherable (Verb)
A writing that is very unclear or untidy or is in a language you don't understand.

- It's completely indecipherable.it is certainly not English
- Maggie's handwriting is virtually indecipherable.
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Scrawl (Verb)
1-To write or draw in a careless,rough, untidy and hasty way.

- Who's scrawled all over the wall?
- He scrawled a hasty note to his wife.
- Jim scrawled his signature/name on the bottom of the page.

2- (Noun) A note ,etc written in this way.

- The letter was handwritten, in a hasty, barely decipherable scrawl.
- His signature was an illegible scrawl.
- The end of the letter was a scrawl, but her signature was clear enough.