un·re·li·able | \ˌən-ri-ˈlī-ə-bəl \

Definition of unreliable 

: not reliable : undependable, untrustworthy an unreliable friend an unreliable source of funding an unreliable car

Keep scrolling for more

Other Words from unreliable

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

But at the height of their powers, giant companies make blinkered, unreliable guides to their own futures. The Economist, "History’s biggest firms," 5 July 2018 The word is often used to write someone off as unreliable or, plainly, mentally ill. Brittney Mcnamara, Teen Vogue, "Kanye West Opened Up About His Mental Health," 1 May 2018 Even with healthy bodies, the Tigers' bullpen is known for being unreliable. George Sipple, Detroit Free Press, "Detroit Tigers takeaways: How adding Jim Adduci impacts James McCann," 3 July 2018 Hundreds of patients paid for blood tests and test results that were inaccurate, unreliable, and improperly validated, and in some cases which had had critical results removed, according to the indictment. Elizabeth Weise, azcentral, "Theranos founder Elizabeth Holmes and former president Balwani charged with federal fraud," 15 June 2018 Our tests of the parking-assist option revealed its performance to be spotty and unreliable, but the lane-keeping system worked as expected. Car and Driver, "2018 Ford Escape," 23 Mar. 2018 His defenders argue that tests on certain pieces of evidence have been unreliable and may reveal tampering. latimes.com, "'They framed me': On death row for decades, Kevin Cooper pushes for new DNA tests in Chino Hills murders," 8 July 2018 In April India celebrated the electrification of its last village, yet about 240m people remain without power and connections are often unreliable. The Economist, "Mini-grids may be the best way to illuminate the “bottom billion”," 12 July 2018 Since the wood is pretty unreliable the safest way across is via the metal girders. Wes Siler, Outside Online, "Doing It for the ‘Gram Turns Deadly," 9 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'unreliable.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of unreliable

1810, in the meaning defined above

Keep scrolling for more

Learn More about unreliable

Share unreliable

Statistics for unreliable

Last Updated

29 Sep 2018

Look-up Popularity

Time Traveler for unreliable

The first known use of unreliable was in 1810

See more words from the same year

Keep scrolling for more

More Definitions for unreliable


un·re·li·able | \ˌən-ri-ˈlī-ə-bəl\

Kids Definition of unreliable

: not worthy of trust He got rid of his unreliable car.

Keep scrolling for more

More from Merriam-Webster on unreliable

Spanish Central: Translation of unreliable

Nglish: Translation of unreliable for Spanish Speakers

Britannica English: Translation of unreliable for Arabic Speakers

Comments on unreliable

What made you want to look up unreliable? Please tell us where you read or heard it (including the quote, if possible).


required by fashion, etiquette, or custom

Get Word of the Day daily email!

Test Your Vocabulary

Great Scrabble Words—A Quiz

  • scrabble-tiles-that-read-scrabble-quiz
  • Which of the following Q-without-U words means the number five in cards or dice?
Spell It

Can you spell these 10 commonly misspelled words?

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!