lie detector

noun

: a polygraph for detecting physiological evidence (such as change in heart rate) of the tension that accompanies lying

Examples of lie detector in a Sentence

The murder suspect failed a lie detector test. hooked the suspect up to a lie detector before interrogating him about the robbery
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
That illusion is enough to fool even a lie detector. Dmitry Mishunin, Forbes, 10 Dec. 2024 The lie detector consists of the blind monk from the crucifix room at the Vatican and a cup of seltzer water. Maggie Fremont, Vulture, 15 Aug. 2024 Riverside, California, investigators linked a man’s DNA to a 1979 cold case murder of a teenage girl, years after the same man passed a lie detector test about the crime, according to authorities. Greg Wehner, Fox News, 25 Nov. 2024 Press play above to see what happens when human lie detector meets skilled liar. Matt Webb Mitovich, TVLine, 21 Oct. 2024 See all Example Sentences for lie detector 

Word History

First Known Use

1909, in the meaning defined above

Time Traveler
The first known use of lie detector was in 1909

Dictionary Entries Near lie detector

Cite this Entry

“Lie detector.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lie%20detector. Accessed 9 Jan. 2025.

Kids Definition

lie detector

noun
: an instrument for detecting bodily changes (as an increase in heart rate) that are considered to go along with lying

Medical Definition

lie detector

noun
: a polygraph for detecting physiological evidence (as change in heart rate) of the tension that accompanies lying

Legal Definition

lie detector

noun
lie de·​tec·​tor
: an instrument for detecting physiological evidence of the tension that accompanies lying compare polygraph

More from Merriam-Webster on lie detector

Last Updated: - Updated example sentences
Love words? Need even more definitions?

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