'Illegibility' definitions:

Definition of 'illegibility'

(from WordNet)
noun
The quality of writing (print or handwriting) that cannot be deciphered [ant: legibility, readability]

Definition of 'Illegibility'

From: GCIDE
  • Illegibility \Il*leg`i*bil"i*ty\, n. The state or quality of being illegible. [1913 Webster]