unreliable

[uhn-ri-lahy-uh-buh l] /ˌʌn rɪˈlaɪ ə bəl/
adjective
1.
not reliable; not to be relied or depended on.
Origin
1830-40; un-1 + reliable
Related forms
unreliability, unreliableness, noun
unreliably, adverb
Synonyms
undependable, irresponsible, untrustworthy.
Examples from the web for unreliable
  • Everyone has heard that memories can be unreliable, but many of us don't appreciate the extent to which that is true.
  • Artificial sprinklers were set up to mimic the natural spray of the falls, but they were unreliable.
  • He had tinkered with it long enough to think it might not be totally unreliable.
  • Moreover, prolonged nursing has been found to be unreliable as a contraceptive.
  • Usage of language is unreliable and is itself in need of examination for its authority.
  • US officials have repeatedly called it unreliable.
  • The surface-to-air missiles are notoriously unreliable.
  • Likewise, it makes no sense to site nuclear power plants where water supplies are scarce or unreliable.
  • Agonizingly slow and chronically unreliable, the cable went dead after three weeks.
  • Tranquilizer darts are often inaccurate, slow-moving, and unreliable.
British Dictionary definitions for unreliable

unreliable

/ˌʌnrɪˈlaɪəbəl/
adjective
1.
not reliable; untrustworthy: an unreliable witness
Word Origin and History for unreliable
adj.

1840, from un- (1) "not" + reliable. First recorded in De Quincey, who said it was coined by Coleridge.