lie detector

noun

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

Synonyms

• polygraph

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

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

Word History

First Known Use

1909, in the meaning defined above

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

ˈlī-di-ˌtek-tər 

: 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