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 rest of the reservation is connected to the grid, but the power is unreliable and outages can sometimes last days. —Nate Perez, NPR, 7 Oct. 2025

This variability makes tungsten diselenide unreliable for quantum applications. —Neetika Walter, Interesting Engineering, 3 Oct. 2025

Much of the country relies on petrol generators because the grid is patchy and unreliable, but unsubsidized fuel is too expensive for most. —semafor.com, 30 Sep. 2025

Wall Street is uneasy, with UBS’s Paul Donovan warning the lack of official data could let rumor and unreliable surveys sway markets, while companies quietly push through price hikes. —Eleanor Pringle, Fortune, 30 Sep. 2025

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