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unreliable

unreliable

71 4.1
Not able to be trusted to work or be right
  • adjective
  • /ˌʌn.rɪˈlaɪ.ə.bəl/
translation icon : poco fiable
  • The weather forecast was unreliable, and it rained even though they predicted sunshine.
  • an unreliable source
  • unreliable data
  • unreliable results

Yes, there are some very unreliable providers.

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Examples

  • Her memory was unreliable, often leading her to remember events incorrectly.

  • Servants have become as unreliable as we are.

  • Yes, there are some very unreliable providers.

  • Cell phone service is so unreliable.

  • The result is unreliable data when it comes to measuring the effectiveness of schools.

    Academic text (2011)
  • Is survey methodology too crude and unreliable to capture the whole picture?

    Academic text (1993)
  • The availability of these chemicals, which depends on foreign exchange, is unreliable and unpredictable.

    Academic text (2008)
  • Wi-Fi can be unreliable when you're trying to do things on the Internet.

  • Voter confusion, endless recounts, unreliable results.

  • Much uncertainty about Himalayan deforestation results from unreliable information about forest product use.

    Academic text (1990)

Synonyms

questionable
vsunreliable
176 3.9

Probably not true or trustworthy

is stronger, stating active inability to be trusted or depended on
inaccurate
vsunreliable
113 4.3

Not correct or exact, with mistakes

is wider, covering unreliability in honesty, behaviour, or performance
faulty
vsunreliable
36 3.5

Not correct because it has mistakes, for example in an argument or plan

focuses instead on being untrustworthy in behaviour or truthfulness
iffy
vsunreliable
  • Informal
26 8.1

Not certain or reliable

is firmer, implying likely to be wrong or to fail rather than just uncertain
untrustworthy
vsunreliable
21 4.8

Not honest or reliable with promises

is broader, also meaning likely to be wrong, misleading, or to fail
dodgy
vsunreliable
  • UK
13 8.2

Likely to be unsafe or untrustworthy

is focused on lack of trust without necessarily implying danger
flaky
vsunreliable
  • Informal
6 7.0

Tending to fail or change without warning

is more general and includes being wrong or intentionally misleading
undependable
vsunreliable
3 4.7

Likely to fail or disappoint people

focuses more on being likely wrong or misleading as well
fly-by-night
vsunreliable
  • Offensive
2 8.9

Not reliable and likely to disappear quickly, often for dishonest reasons

is more general and covers any kind of not being dependable
error-prone
vsunreliable
2 5.1

Tends to make many mistakes

is broader, including deliberate misleading or failure to perform
trustless
vsunreliable
8.1

A situation where people do not feel safe and avoid honest conversation

adds that this often includes being likely to be wrong or fail
untrusty
vsunreliable
  • Archaic
8.9

Not safe to depend on because they may fail or betray you

stresses practical failure or misleading behaviour in addition to doubt

Antonyms

358 2.7

Able to be trusted to do what is expected

88 2.1

A person or thing you can depend on to be honest

How Reliable

dependable
47 2.3
reliable
358 2.7
inconsistent
96 4.7
unreliable
71 4.1
untrustworthy
21 4.8

Surface Forms

unreliable positive
unreliabler comparative
unreliablest superlative

Morphology

unreliable = reliable (transparent) = un + rely + able

The negative prefix 'un-' is attached to the familiar adjective 'reliable', producing the straightforward opposite meaning.

Etymology

Unreliable is made of the parts un- meaning 'not', rely meaning 'depend on', and -able meaning 'can be'. So it literally says 'not able to be depended on', which is why it means someone or something you cannot trust.