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

Voters are paying for aging, dirty and unreliable coal plants that often aren’t even running or working. — David Kieve, Time, 10 July 2026

When buses are slow and unreliable, those burdens fall disproportionately on these communities. — Mike Flynn, New York Daily News, 9 July 2026

An unreliable supplier is more costly than the difference between the two price quotes. — Lyssanoel Frater, USA Today, 8 July 2026

Aviv’s journalistic method leans on the idea of unreliable narration. — Julia M. Klein, Los Angeles Times, 8 July 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