unreliable

adjective

un·​re·​li·​able ˌən-ri-ˈlī-ə-bəl How to pronounce unreliable (audio)
Synonyms of unreliablenext
: not reliable : undependable, untrustworthy
an unreliable friend
an unreliable source of funding
an unreliable car
unreliability
ˌən-ri-ˌlī-ə-ˈbi-lə-tē How to pronounce unreliable (audio)
noun
the unreliability of the data
a person with a reputation for unreliability
unreliably
ˌən-ri-ˈlī-ə-blē How to pronounce unreliable (audio)
adverb
a method that works unreliably

Examples of unreliable in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Girls such as Zainab have been pushed out of the classroom entirely and left to depend on costly, unreliable alternatives. — Fatima Faizi, NPR, 14 Aug. 2026 That capability could matter when traditional supply routes become slow or unreliable. — Aamir Khollam, Interesting Engineering, 12 Aug. 2026 Summary Global crude oil markets are plagued by confusion due to unreliable data, hindering accurate assessments by analysts and companies. — David Blackmon, Forbes.com, 12 Aug. 2026 Yet a 2023 Stanford study said that Pangram was biased against non-native English speakers, who might have more limited vocabularies, and many AI researchers contend that such detectors are unreliable. — Cameron Pugh, Christian Science Monitor, 12 Aug. 2026 See All Example Sentences for unreliable

Word History

First Known Use

1810, in the meaning defined above

Time Traveler
The first known use of unreliable was in 1810

Rhymes for unreliable

See All Rhymes for unreliable

Browse Nearby Words

unreliability
unreliable
unrelievable
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Cite this Entry

“Unreliable.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unreliable. Accessed 16 Aug. 2026.

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More from Merriam-Webster on unreliable

Thesaurus: All synonyms and antonyms for unreliable

Nglish: Translation of unreliable for Spanish Speakers

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