What does illegible mean?
Illegible describes writing, print, or markings that cannot be read because they are too faint, blurred, damaged, crowded, or otherwise unclear. It is often used for documents, manuscripts, signatures, handwriting, and inscriptions, and it conveys that legibility may require better lighting, restoration, or specialized interpretation. The word can also suggest that something is difficult to decipher because of poor organization, obscurity, or poor communication rather than physical damage. Its opposite is legible, meaning clear enough to read, while readable is a more general alternative. In everyday descriptions, illegible often communicates the practical consequence of bad image quality or deterioration, while the Latin-derived form gives the description a somewhat formal, authoritative tone.
adjectiveNot legible; impossible or very difficult to read or decipher.
- Unable to be read or deciphered, especially because the writing is faint, distorted, damaged, or otherwise unclear.
"The faint, illegible message was impossible to read."
"Her signature was almost illegible at the bottom of the form."
"Much of the oldest manuscript remains illegible despite careful imaging and restoration."
Sometimes the clearest description of a document is the one it cannot offer: it is simply illegible.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does illegible come from?
Illegible was formed in English in the late 16th century from the Latin prefix il-, meaning “not,” and legible, from Latin legibilis, meaning “able to be read.” The underlying Latin verb legere means “to read” or “to gather,” and its derivatives include legible, legibility, and intellect. English later added the negative form illegible to describe writing that could not be deciphered.
Related word forms
How illegible is actually used
The term is formal but widely understood. It is usually applied to writing, text, documents, or markings rather than to people.
Easily confused with illegible
Legible means clear enough to be read, whereas illegible means too unclear or indistinct to read.
Illegible describes writing or text that cannot be read, while eligible means qualified or permitted to do something.