not readable; undecipherable; scribbled

His scrawl was almost unreadable.

not interesting to read; dull; tedious; an unreadable treatise.

extraordinarily difficult to read or comprehend; obscure; incomprehensible

an unreadable dream; an unreadable expression.

adjective

cacographic , crabbed , difficult to read , hard to make out , incomprehensible , indecipherable , scrawled , scribbled , unclear , undecipherablenotes:illegible refers to bad handwriting , while unreadable refers to poor writing , illegible