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.

If the Strait of Hormuz becomes unreliable, energy can be sourced from the U.S. or transported via Saudi Arabia’s East-West pipeline.

From MarketWatch • Apr. 9, 2026

But polygraphs are unreliable and inadmissible in court, and Hatley maintained her innocence under further questioning.

From Slate • Apr. 6, 2026

While these systems are powerful, they consume large amounts of energy and can still produce unreliable results.

From Science Daily • Apr. 5, 2026

“Forecasting and prediction is still a very challenging and unreliable domain for AI,” he said.

From The Wall Street Journal • Mar. 24, 2026

Opinion, experience and persuasion were necessarily unreliable and unsatisfactory; knowledge had to be built on firmer foundations.

From "The Invention of Science" by David Wootton

Vocabulary lists containing unreliable

STAAR English I: Elements of Literature

Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!

STAAR English II: Elements of Literature 1

Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!

Point of View

Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!