Definitions

unreliable

[uhn-ri-lahy-uh-buhl] / ˌʌn rɪˈlaɪ ə bəl /

ADJECTIVE

not trustworthy, not true

Synonyms

STRONGEST

capricious deceptive dubious false fickle inaccurate irresponsible treacherous tricky uncertain unsound unstable untrustworthy

STRONG

undependable

WEAK

deceitful delusive disreputable erroneous fake fallible fly-by-night furtive hallucinatory hollow implausible inconstant makeshift meretricious mistaken pretended pseudo questionable sham shifty specious unconvincing underhand underhanded unfaithful unsure untrue vacillating wavering weak

Antonyms

STRONGEST

accurate certain clear constant correct definite dependable faithful forthright frank honest reliable right stable steady strong sure true trustworthy truthful

WEAK

responsible

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Polling in mayoral races is typically pretty unreliable.

From Los Angeles Times • Jun. 1, 2026

Mobile data can be unreliable, too - especially when trains travel through tunnels.

From BBC • May 30, 2026

“Slop,” executives declared, a total of 17 times, during a call with investors this past week, portraying the outputs of the major AI labs as too messy and unreliable for big enterprises.

From The Wall Street Journal • May 9, 2026

Rooney would also start James on the right side of defence this summer, despite calling the 26-year-old "unreliable" as a full-back.

From BBC • May 8, 2026

By then, my mother had acquired a motor-boat, a small and not very seaworthy white wooden vessel which sat far too low in the water and was powered by an unreliable one-cylinder engine.

From "Boy: Tales of a Childhood" by Roald Dahl

Vocabulary lists containing unreliable

STAAR English I: Elements of Literature

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STAAR English II: Elements of Literature 1

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Point of View

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