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

Either way, the audience is expected to take the course of events with a grain of salt, as Weisz's character is a classic unreliable narrator. —Meg Walters, Glamour, 9 Mar. 2026

On match days, that estimate becomes unreliable. —Allison Palmer, Sacbee.com, 9 Mar. 2026

Cadillac, though, won’t be taking any heart from finishing ahead of Aston Martin, which had a nightmare season start with an uncompetitive and unreliable Honda power unit that cost it mileage to make improvements; ensuring the team is destined to be at the back for the foreseeable future. —ABC News, 8 Mar. 2026

The Broncos’ offensive line ranks near the top of the pack, and somehow the run game remains mediocre or, as in the case of a huge fourth down in the AFC Championship, unreliable. —Troy Renck, Denver Post, 8 Mar. 2026

Word History

First Known Use

1810, in the meaning defined above

Rhymes for unreliable

• leviable
• reliable
• classifiable
• justifiable
• modifiable
• notifiable
• satisfiable
• specifiable
• undeniable
• verifiable
• emulsifiable
• identifiable