Source : Webster's Revised Unabridged Dictionary (1913)

Unreliable \Un`re*li"a*ble\, a.
   Not reliable; untrustworthy. See {Reliable}. --
   {Un`re*li"a*ble*ness}, n.

         Alcibiades . . . was too unsteady, and (according to
         Mr. Coleridge's coinage) ``unreliable;'' or perhaps, in
         more correct English, too ``unrelyuponable.'' --De
                                                  Quincey.

Source : WordNet®

unreliableness
     n : the trait of not being dependable or reliable [syn: {undependability},
          {undependableness}, {unreliability}] [ant: {dependability},
          {dependability}, {dependability}, {dependability}]