IPA: /ɪlˈɛdʒəˌbɪlɪti/
KK: /ɪlˈɛdʒəˌbɪlɪti/
The quality of being hard to read or unclear in writing or print.
The illegibility of the note made it impossible to understand the message.
Illegibility is formed from "il-" (meaning not), "legere" (meaning to read), and "-ibility" (meaning the quality of being). The word describes the quality of being not readable or difficult to read.
Think of 'not' ('il-') being combined with 'read' ('legere') to remember that 'illegibility' means something that is not readable.