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

According to Rose, weeks without rain can force them to conserve water, while prolonged storms can leave them with less solar power and unreliable Wi-Fi. — Tereza Shkurtaj, PEOPLE, 9 Nov. 2026

If its data becomes outdated or its model fails to account for changing conditions, its predictions can become unreliable. — Kaif Shaikh, Interesting Engineering, 8 Nov. 2026

As bad actors have become more sophisticated by using AI to manufacture synthetic identities and automate account takeovers, static signals are increasingly unreliable. — Jess Turner, Forbes.com, 6 Nov. 2026

Kohler is the text—to even classify him as an ‘unreliable narrator’ would be senseless, as there is no external truth to judge him against. — Literary Hub, 5 Nov. 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