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

The leggings were still wet, heavily soiled, and badly deteriorated, LaHendro testified, making the edge detail too unreliable for comparison. — Nancy Dillon, Rolling Stone, 24 July 2026

As code generation becomes more accessible, the ability to identify inaccurate or unreliable outputs may become increasingly valuable. — Felysha Walker, Kansas City Star, 24 July 2026

The other is the data gap itself, with unreliable or incomplete records common across stormwater systems, levees, schools and other sectors. — Dara-Abasi Ita, Forbes.com, 23 July 2026

Inadequate home wiring and unreliable electrical grids present additional challenges in many places. — Ashwini Sehgal, The Conversation, 23 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