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

Among the 41 characters portrayed as having narcolepsy, 68% were depicted as incapable or unreliable. — Sandee Lamotte, CNN Money, 22 Sep. 2026

Perhaps a future edition could include a chapter reflecting on whether these kinds of politicians also make for unreliable candidates. — Isaac Arnsdorf, New Yorker, 18 Sep. 2026

Officials said public feedback collected through workshops, stakeholder meetings, pop-up events and previous surveys has identified congestion, unreliable travel times, safety and limited alternatives to driving as recurring concerns. — Nicole Buss, Sacbee.com, 18 Sep. 2026

These doubters also disparage as unreliable or wishful thinking the oral histories passed down by Hemings’s descendants who have placed Jefferson in their family tree. — Andrew Lawler, The Atlantic, 18 Sep. 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