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

Filmed in conjunction with Grande and Erivo’s joint Vanity Fair cover story, the lie detector test also gave the R.E.M. Beauty founder an opportunity to set the record straight on numerous plastic surgery rumors that have followed her over the past couple of years. —Hannah Dailey, Billboard, 30 Sep. 2024

And last season’s bonus episode saw cast members take a lie detector test, which divulged that the Oppenheim Group founder still had feelings for Stause. —Erin Clements, Peoplemag, 12 Sep. 2024

But while Kyle talked up the accuracy of the lie detectors, they have been called into question since the show was axed almost immediately after Dymond took his own life. —Max Goldbart, Deadline, 5 Sep. 2024

And does this critical investigation require a DNA test, a lie detector test, or both? —Lorraine Ali, Los Angeles Times, 1 Aug. 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