Il*leg"i*ble*ness

from The Collaborative International Dictionary of English v.0.48

Illegible \Il*leg"i*ble\, a.
   Incapable of being read; not legible; as, illegible
   handwriting; an illegible inscription. --
   {Il*leg"i*ble*ness}, n. -- {Il*leg"i*bly}, adv.
   [1913 Webster]