unreliable

adjective

un·​re·​li·​able ˌən-ri-ˈlī-ə-bəl 

: not reliable : undependable, untrustworthy

an unreliable friend

an unreliable source of funding

an unreliable car

unreliability

ˌən-ri-ˌlī-ə-ˈbi-lə-tē 

noun

the unreliability of the data

a person with a reputation for unreliability

unreliably

ˌən-ri-ˈlī-ə-blē 

adverb

a method that works unreliably

Examples of unreliable in a Sentence

Recent Examples on the Web

Yet, the company’s machines really could only perform a limited number of tests and often produced unreliable results. — Marco Quiroz-Gutierrez, Fortune, 21 Oct. 2026

Potential applications include autonomous drones, submarines and other vehicles operating in environments where satellite navigation is unreliable. — Neetika Walter, Interesting Engineering, 17 Oct. 2026

As Puerto Rico continues to grapple with the long aftermath of Hurricane Maria — from an unreliable electrical grid to ongoing water shortages — the need for stories that see the island as more than a backdrop feels especially urgent. — Johanna Ferreira, Los Angeles Times, 16 Oct. 2026

Even so, officials recommend residents consider backup ways to communicate in case cell service is unreliable. — Sarah Horbacewicz, CBS News, 15 Oct. 2026

Word History

First Known Use

1810, in the meaning defined above

Rhymes for unreliable

• liable
• pliable
• triable
• viable
• classifiable
• justifiable
• modifiable
• notifiable
• satisfiable
• specifiable
• undeniable
• verifiable