lie detector

noun

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

Synonyms of lie detector

• 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

In the trailer, the Wicked Oscar nominee can be seen in the hot seat, continuing the Focker family tradition of being interviewed while strapped to a lie detector test. —Yamillah Hurtado, PEOPLE, 16 Apr. 2026

Though Earle left Cooper’s Unwell Network months before Johnson chimed in during her Vanity Fair lie detector test in June 2025, nothing was ever confirmed on what went down between the two women and why Earle parted ways with Cooper’s company in March 2025. —Carly Thomas, HollywoodReporter, 16 Apr. 2026

This is Ariana Grande’s, what, third time in a lie detector? —Bethy Squires, Vulture, 16 Apr. 2026

In his letter to Weber, Curtis promised to take a lie detector test after each election. —Los Angeles Times, 25 Mar. 2026

Word History

First Known Use

1909, in the meaning defined above

Rhymes for lie detector

• eigenvector
• bisector
• collector
• connector
• corrector
• defector
• deflector
• director
• dissector
• effector
• ejector
• elector

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