unreliable Meaning, Definition & Usage

  1. adjective satellite liable to be erroneous or misleading
    undependable.
    • an undependable generalization
  2. adjective not worthy of reliance or trust
    undependable.
    • in the early 1950s computers were large and expensive and unreliable
    • an undependable assistant
  3. adjective satellite dangerously unstable and unpredictable
    treacherous.
    • treacherous winding roads
    • an unreliable trestle
  4. adjective satellite lacking a sense of responsibility

WordNet

Un`re*li"a*ble adjective
Definitions
  1. 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.

Webster 1913